Class String

java.lang.Object
java.lang.String
All Implemented Interfaces:
Serializable,CharSequence,Comparable<String>,Constable,ConstantDesc
public final classStringextendsObjectimplementsSerializable,Comparable<String>,CharSequence,Constable,ConstantDesc
TheString class represents character strings. Allstring literals in Java programs, such as"abc", areimplemented as instances of this class.

Strings are constant; their values cannot be changed after theyare created. String buffers support mutable strings.Because String objects are immutable they can be shared. For example:

    String str = "abc";

is equivalent to:

    char data[] = {'a', 'b', 'c'};    String str = new String(data);

Here are some more examples of how strings can be used:

    System.out.println("abc");    String cde = "cde";    System.out.println("abc" + cde);    String c = "abc".substring(2, 3);    String d = cde.substring(1, 2);

The classString includes methods for examiningindividual characters of the sequence, for comparing strings, forsearching strings, for extracting substrings, and for creating acopy of a string with all characters translated to uppercase or tolowercase. Case mapping is based on the Unicode Standard versionspecified by theCharacter class.

The Java language provides special support for the stringconcatenation operator ( + ), and for conversion ofother objects to strings. For additional information on stringconcatenation and conversion, seeThe Java Language Specification.

Unless otherwise noted, passing anull argument to a constructoror method in this class will cause aNullPointerException to bethrown.

AString represents a string in the UTF-16 formatin whichsupplementary characters are represented bysurrogatepairs (see the sectionUnicodeCharacter Representations in theCharacter class formore information).Index values refer tochar code units, so a supplementarycharacter uses two positions in aString.

TheString class provides methods for dealing withUnicode code points (i.e., characters), in addition to those fordealing with Unicode code units (i.e.,char values).

Unless otherwise noted, methods for comparing Strings do not take localeinto account. TheCollator class provides methods forfiner-grain, locale-sensitive String comparison.

Implementation Note:
The implementation of the string concatenation operator is left tothe discretion of a Java compiler, as long as the compiler ultimately conformstoThe Java Language Specification. For example, thejavac compilermay implement the operator withStringBuffer,StringBuilder,orjava.lang.invoke.StringConcatFactory depending on the JDK version. Theimplementation of string conversion is typically through the methodtoString,defined byObject and inherited by all classes in Java.
SeeJava Language Specification:
15.18.1 String Concatenation Operator +
Since:
1.0
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static finalComparator<String>
    A Comparator that ordersString objects as bycompareToIgnoreCase.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Initializes a newly createdString object so that it representsan empty character sequence.
    String(byte[] bytes)
    Constructs a newString by decoding the specified array of bytesusing thedefault charset.
    String(byte[] ascii, int hibyte)
    Deprecated.
    This method does not properly convert bytes intocharacters.
    String(byte[] bytes, int offset, int length)
    Constructs a newString by decoding the specified subarray ofbytes using thedefault charset.
    String(byte[] ascii, int hibyte, int offset, int count)
    Deprecated.
    This method does not properly convert bytes into characters.
    String(byte[] bytes, int offset, int length,String charsetName)
    Constructs a newString by decoding the specified subarray ofbytes using the specified charset.
    String(byte[] bytes, int offset, int length,Charset charset)
    Constructs a newString by decoding the specified subarray ofbytes using the specifiedcharset.
    String(byte[] bytes,String charsetName)
    Constructs a newString by decoding the specified array of bytesusing the specifiedcharset.
    String(byte[] bytes,Charset charset)
    Constructs a newString by decoding the specified array ofbytes using the specifiedcharset.
    String(char[] value)
    Allocates a newString so that it represents the sequence ofcharacters currently contained in the character array argument.
    String(char[] value, int offset, int count)
    Allocates a newString that contains characters from a subarrayof the character array argument.
    String(int[] codePoints, int offset, int count)
    Allocates a newString that contains characters from a subarrayof theUnicode code point arrayargument.
    String(String original)
    Initializes a newly createdString object so that it representsthe same sequence of characters as the argument; in other words, thenewly created string is a copy of the argument string.
    Allocates a new string that contains the sequence of characterscurrently contained in the string buffer argument.
    Allocates a new string that contains the sequence of characterscurrently contained in the string builder argument.

  • Method Summary

    Modifier and Type
    Method
    Description
    char
    charAt(int index)
    Returns thechar value at thespecified index.
    Returns a stream ofint zero-extending thechar valuesfrom this sequence.
    int
    codePointAt(int index)
    Returns the character (Unicode code point) at the specifiedindex.
    int
    codePointBefore(int index)
    Returns the character (Unicode code point) before the specifiedindex.
    int
    codePointCount(int beginIndex, int endIndex)
    Returns the number of Unicode code points in the specified textrange of thisString.
    Returns a stream of code point values from this sequence.
    int
    compareTo(String anotherString)
    Compares two strings lexicographically.
    int
    Compares two strings lexicographically, ignoring casedifferences.
    Concatenates the specified string to the end of this string.
    boolean
    Returns true if and only if this string contains the specifiedsequence of char values.
    boolean
    Compares this string to the specifiedCharSequence.
    boolean
    Compares this string to the specifiedStringBuffer.
    staticString
    copyValueOf(char[] data)
    Equivalent tovalueOf(char[]).
    staticString
    copyValueOf(char[] data, int offset, int count)
    Returns anOptional containing the nominal descriptor for thisinstance, which is the instance itself.
    boolean
    endsWith(String suffix)
    Tests if this string ends with the specified suffix.
    boolean
    equals(Object anObject)
    Compares this string to the specified object.
    boolean
    equalsIgnoreCase(String anotherString)
    Compares thisString to anotherString, ignoring caseconsiderations.
    staticString
    format(String format,Object... args)
    Returns a formatted string using the specified format string andarguments.
    staticString
    format(Locale l,String format,Object... args)
    Returns a formatted string using the specified locale, format string,and arguments.
    formatted(Object... args)
    Formats using this string as the format string, and the suppliedarguments.
    byte[]
    Encodes thisString into a sequence of bytes using thedefault charset, storing the resultinto a new byte array.
    void
    getBytes(int srcBegin, int srcEnd, byte[] dst, int dstBegin)
    Deprecated.
    This method does not properly convert characters intobytes.
    byte[]
    getBytes(String charsetName)
    Encodes thisString into a sequence of bytes using the namedcharset, storing the result into a new byte array.
    byte[]
    getBytes(Charset charset)
    Encodes thisString into a sequence of bytes using the givencharset, storing the result into anew byte array.
    void
    getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
    Copies characters from this sequence into the given destination array.
    int
    Returns a hash code for this string.
    indent(int n)
    Adjusts the indentation of each line of this string based on the value ofn, and normalizes line termination characters.
    int
    indexOf(int ch)
    Returns the index within this string of the first occurrence ofthe specified character.
    int
    indexOf(int ch, int fromIndex)
    Returns the index within this string of the first occurrence of thespecified character, starting the search at the specified index.
    int
    indexOf(int ch, int beginIndex, int endIndex)
    Returns the index within this string of the first occurrence of thespecified character, starting the search atbeginIndex andstopping beforeendIndex.
    int
    Returns the index within this string of the first occurrence of thespecified substring.
    int
    indexOf(String str, int fromIndex)
    Returns the index within this string of the first occurrence of thespecified substring, starting at the specified index.
    int
    indexOf(String str, int beginIndex, int endIndex)
    Returns the index of the first occurrence of the specified substringwithin the specified index range ofthis string.
    Returns a canonical representation for the string object.
    boolean
    Returnstrue if the string isempty or containsonlywhite space codepoints,otherwisefalse.
    boolean
    Returnstrue if, and only if,length() is0.
    staticString
    join(CharSequence delimiter,CharSequence... elements)
    Returns a new String composed of copies of theCharSequence elements joined together with a copy ofthe specifieddelimiter.
    staticString
    join(CharSequence delimiter,Iterable<? extendsCharSequence> elements)
    Returns a newString composed of copies of theCharSequence elements joined together with a copy of thespecifieddelimiter.
    int
    lastIndexOf(int ch)
    Returns the index within this string of the last occurrence ofthe specified character.
    int
    lastIndexOf(int ch, int fromIndex)
    Returns the index within this string of the last occurrence ofthe specified character, searching backward starting at thespecified index.
    int
    Returns the index within this string of the last occurrence of thespecified substring.
    int
    lastIndexOf(String str, int fromIndex)
    Returns the index within this string of the last occurrence of thespecified substring, searching backward starting at the specified index.
    int
    Returns the length of this string.
    Returns a stream of lines extracted from this string,separated by line terminators.
    boolean
    matches(String regex)
    Tells whether or not this string matches the givenregular expression.
    int
    offsetByCodePoints(int index, int codePointOffset)
    Returns the index within thisString that isoffset from the givenindex bycodePointOffset code points.
    boolean
    regionMatches(boolean ignoreCase, int toffset,String other, int ooffset, int len)
    Tests if two string regions are equal.
    boolean
    regionMatches(int toffset,String other, int ooffset, int len)
    Tests if two string regions are equal.
    repeat(int count)
    Returns a string whose value is the concatenation of thisstring repeatedcount times.
    replace(char oldChar, char newChar)
    Returns a string resulting from replacing all occurrences ofoldChar in this string withnewChar.
    replace(CharSequence target,CharSequence replacement)
    Replaces each substring of this string that matches the literal targetsequence with the specified literal replacement sequence.
    replaceAll(String regex,String replacement)
    Replaces each substring of this string that matches the givenregular expression with the given replacement.
    replaceFirst(String regex,String replacement)
    Replaces the first substring of this string that matches the givenregular expression with the given replacement.
    Resolves this instance as aConstantDesc, the result of which isthe instance itself.
    split(String regex)
    Splits this string around matches of the givenregular expression.
    split(String regex, int limit)
    Splits this string around matches of the givenregular expression.
    splitWithDelimiters(String regex, int limit)
    Splits this string around matches of the given regular expression andreturns both the strings and the matching delimiters.
    boolean
    Tests if this string starts with the specified prefix.
    boolean
    startsWith(String prefix, int toffset)
    Tests if the substring of this string beginning at thespecified index starts with the specified prefix.
    Returns a string whose value is this string, with all leadingand trailingwhite spaceremoved.
    Returns a string whose value is this string, with incidentalwhite space removed fromthe beginning and end of every line.
    Returns a string whose value is this string, with all leadingwhite space removed.
    Returns a string whose value is this string, with all trailingwhite space removed.
    subSequence(int beginIndex, int endIndex)
    Returns a character sequence that is a subsequence of this sequence.
    substring(int beginIndex)
    Returns a string that is a substring of this string.
    substring(int beginIndex, int endIndex)
    Returns a string that is a substring of this string.
    char[]
    Converts this string to a new character array.
    Converts all of the characters in thisString to lowercase using the rules of the default locale.
    Converts all of the characters in thisString to lowercase using the rules of the givenLocale.
    This object (which is already a string!)
    Converts all of the characters in thisString to uppercase using the rules of the default locale.
    Converts all of the characters in thisString to uppercase using the rules of the givenLocale.
    <R> R
    transform(Function<? superString, ? extends R> f)
    This method allows the application of a function tothisstring.
    Returns a string whose value is this string, with escape sequencestranslated as if in a string literal.
    Returns a string whose value is this string, with all leadingand trailing space removed, where space is definedas any character whose codepoint is less than or equal to'U+0020' (the space character).
    staticString
    valueOf(boolean b)
    Returns the string representation of theboolean argument.
    staticString
    valueOf(char c)
    Returns the string representation of thecharargument.
    staticString
    valueOf(char[] data)
    Returns the string representation of thechar arrayargument.
    staticString
    valueOf(char[] data, int offset, int count)
    Returns the string representation of a specific subarray of thechar array argument.
    staticString
    valueOf(double d)
    Returns the string representation of thedouble argument.
    staticString
    valueOf(float f)
    Returns the string representation of thefloat argument.
    staticString
    valueOf(int i)
    Returns the string representation of theint argument.
    staticString
    valueOf(long l)
    Returns the string representation of thelong argument.
    staticString
    Returns the string representation of theObject argument.

  • Field Details

    • CASE_INSENSITIVE_ORDER

      public static final Comparator<String> CASE_INSENSITIVE_ORDER
      A Comparator that ordersString objects as bycompareToIgnoreCase.This comparator is serializable.

      Note that this Comparator doesnot take locale into account,and will result in an unsatisfactory ordering for certain locales.TheCollator class provides locale-sensitive comparison.

      Since:
      1.2
      See Also:

  • Constructor Details

    • String

      public String()
      Initializes a newly createdString object so that it representsan empty character sequence. Note that use of this constructor isunnecessary since Strings are immutable.

    • String

      public String(String original)
      Initializes a newly createdString object so that it representsthe same sequence of characters as the argument; in other words, thenewly created string is a copy of the argument string. Unless anexplicit copy oforiginal is needed, use of this constructor isunnecessary since Strings are immutable.
      Parameters:
      original - AString

    • String

      public String(char[] value)
      Allocates a newString so that it represents the sequence ofcharacters currently contained in the character array argument. Thecontents of the character array are copied; subsequent modification ofthe character array does not affect the newly created string.

      The contents of the string are unspecified if the character arrayis modified during string construction.

      Parameters:
      value - The initial value of the string

    • String

      public String(char[] value, int offset, int count)
      Allocates a newString that contains characters from a subarrayof the character array argument. Theoffset argument is theindex of the first character of the subarray and thecountargument specifies the length of the subarray. The contents of thesubarray are copied; subsequent modification of the character array doesnot affect the newly created string.

      The contents of the string are unspecified if the character arrayis modified during string construction.

      Parameters:
      value - Array that is the source of characters
      offset - The initial offset
      count - The length
      Throws:
      IndexOutOfBoundsException - Ifoffset is negative,count is negative, oroffset is greater thanvalue.length - count

    • String

      public String(int[] codePoints, int offset, int count)
      Allocates a newString that contains characters from a subarrayof theUnicode code point arrayargument. Theoffset argument is the index of the first codepoint of the subarray and thecount argument specifies thelength of the subarray. The contents of the subarray are converted tochars; subsequent modification of theint array does notaffect the newly created string.

      The contents of the string are unspecified if the codepoints arrayis modified during string construction.

      Parameters:
      codePoints - Array that is the source of Unicode code points
      offset - The initial offset
      count - The length
      Throws:
      IllegalArgumentException - If any invalid Unicode code point is found in codePoints
      IndexOutOfBoundsException - Ifoffset is negative,count is negative, oroffset is greater thancodePoints.length - count
      Since:
      1.5

    • String

      @Deprecated(since="1.1")public String(byte[] ascii, int hibyte, int offset, int count)
      Deprecated.
      This method does not properly convert bytes into characters.As of JDK 1.1, the preferred way to do this is via theString constructors that take aCharset, charset name,or that use thedefault charset.
      Allocates a newString constructed from a subarray of an arrayof 8-bit integer values.

      Theoffset argument is the index of the first byte of thesubarray, and thecount argument specifies the length of thesubarray.

      Eachbyte in the subarray is converted to achar asspecified in theString(byte[],int) constructor.

      The contents of the string are unspecified if the byte arrayis modified during string construction.

      Parameters:
      ascii - The bytes to be converted to characters
      hibyte - The top 8 bits of each 16-bit Unicode code unit
      offset - The initial offset
      count - The length
      Throws:
      IndexOutOfBoundsException - Ifoffset is negative,count is negative, oroffset is greater thanascii.length - count
      See Also:

    • String

      @Deprecated(since="1.1")public String(byte[] ascii, int hibyte)
      Deprecated.
      This method does not properly convert bytes intocharacters. As of JDK 1.1, the preferred way to do this is via theString constructors that take aCharset, charset name,or that use thedefault charset.
      Allocates a newString containing characters constructed froman array of 8-bit integer values. Each characterc in theresulting string is constructed from the corresponding componentb in the byte array such that:
      c == (char)(((hibyte & 0xff) << 8)                        | (b & 0xff))

      The contents of the string are unspecified if the byte arrayis modified during string construction.

      Parameters:
      ascii - The bytes to be converted to characters
      hibyte - The top 8 bits of each 16-bit Unicode code unit
      See Also:

    • String

      public String(byte[] bytes, int offset, int length,String charsetName) throwsUnsupportedEncodingException
      Constructs a newString by decoding the specified subarray ofbytes using the specified charset. The length of the newStringis a function of the charset, and hence may not be equal to the lengthof the subarray.

      The behavior of this constructor when the given bytes are not validin the given charset is unspecified. TheCharsetDecoder class should be used when more controlover the decoding process is required.

      The contents of the string are unspecified if the byte arrayis modified during string construction.

      Parameters:
      bytes - The bytes to be decoded into characters
      offset - The index of the first byte to decode
      length - The number of bytes to decode
      charsetName - The name of a supportedcharset
      Throws:
      UnsupportedEncodingException - If the named charset is not supported
      IndexOutOfBoundsException - Ifoffset is negative,length is negative, oroffset is greater thanbytes.length - length
      Since:
      1.1

    • String

      public String(byte[] bytes, int offset, int length,Charset charset)
      Constructs a newString by decoding the specified subarray ofbytes using the specifiedcharset.The length of the newString is a function of the charset, andhence may not be equal to the length of the subarray.

      This method always replaces malformed-input and unmappable-charactersequences with this charset's default replacement string. TheCharsetDecoder class should be used when more controlover the decoding process is required.

      The contents of the string are unspecified if the byte arrayis modified during string construction.

      Parameters:
      bytes - The bytes to be decoded into characters
      offset - The index of the first byte to decode
      length - The number of bytes to decode
      charset - Thecharset to be used to decode thebytes
      Throws:
      IndexOutOfBoundsException - Ifoffset is negative,length is negative, oroffset is greater thanbytes.length - length
      Since:
      1.6

    • String

      public String(byte[] bytes,String charsetName) throwsUnsupportedEncodingException
      Constructs a newString by decoding the specified array of bytesusing the specifiedcharset. Thelength of the newString is a function of the charset, and hencemay not be equal to the length of the byte array.

      The behavior of this constructor when the given bytes are not validin the given charset is unspecified. TheCharsetDecoder class should be used when more controlover the decoding process is required.

      The contents of the string are unspecified if the byte arrayis modified during string construction.

      Parameters:
      bytes - The bytes to be decoded into characters
      charsetName - The name of a supportedcharset
      Throws:
      UnsupportedEncodingException - If the named charset is not supported
      Since:
      1.1

    • String

      public String(byte[] bytes,Charset charset)
      Constructs a newString by decoding the specified array ofbytes using the specifiedcharset.The length of the newString is a function of the charset, andhence may not be equal to the length of the byte array.

      This method always replaces malformed-input and unmappable-charactersequences with this charset's default replacement string. TheCharsetDecoder class should be used when more controlover the decoding process is required.

      The contents of the string are unspecified if the byte arrayis modified during string construction.

      Parameters:
      bytes - The bytes to be decoded into characters
      charset - Thecharset to be used to decode thebytes
      Since:
      1.6

    • String

      public String(byte[] bytes, int offset, int length)
      Constructs a newString by decoding the specified subarray ofbytes using thedefault charset.The length of the newString is a function of the charset,and hence may not be equal to the length of the subarray.

      The behavior of this constructor when the given bytes are not validin the default charset is unspecified. TheCharsetDecoder class should be used when more controlover the decoding process is required.

      The contents of the string are unspecified if the byte arrayis modified during string construction.

      Parameters:
      bytes - The bytes to be decoded into characters
      offset - The index of the first byte to decode
      length - The number of bytes to decode
      Throws:
      IndexOutOfBoundsException - Ifoffset is negative,length is negative, oroffset is greater thanbytes.length - length
      Since:
      1.1

    • String

      public String(byte[] bytes)
      Constructs a newString by decoding the specified array of bytesusing thedefault charset. The lengthof the newString is a function of the charset, and hence may notbe equal to the length of the byte array.

      The behavior of this constructor when the given bytes are not validin the default charset is unspecified. TheCharsetDecoder class should be used when more controlover the decoding process is required.

      The contents of the string are unspecified if the byte arrayis modified during string construction.

      Parameters:
      bytes - The bytes to be decoded into characters
      Since:
      1.1

    • String

      public String(StringBuffer buffer)
      Allocates a new string that contains the sequence of characterscurrently contained in the string buffer argument. The contents of thestring buffer are copied; subsequent modification of the string bufferdoes not affect the newly created string.
      Parameters:
      buffer - AStringBuffer

    • String

      public String(StringBuilder builder)
      Allocates a new string that contains the sequence of characterscurrently contained in the string builder argument. The contents of thestring builder are copied; subsequent modification of the string builderdoes not affect the newly created string.

      The contents of the string are unspecified if theStringBuilderis modified during string construction.

      This constructor is provided to ease migration toStringBuilder. Obtaining a string from a string builder via thetoString method is likely to run faster and is generally preferred.

      Parameters:
      builder - AStringBuilder
      Since:
      1.5

  • Method Details

    • length

      public int length()
      Returns the length of this string.The length is equal to the number ofUnicodecode units in the string.
      Specified by:
      length in interface CharSequence
      Returns:
      the length of the sequence of characters represented by this object.

    • isEmpty

      public boolean isEmpty()
      Returnstrue if, and only if,length() is0.
      Specified by:
      isEmpty in interface CharSequence
      API Note:
      To determine whether a string contains onlywhite space, useisBlank.
      Returns:
      true iflength() is0, otherwisefalse
      Since:
      1.6

    • charAt

      public char charAt(int index)
      Returns thechar value at thespecified index. An index ranges from0 tolength() - 1. The firstchar value of the sequenceis at index0, the next at index1,and so on, as for array indexing.

      If thechar value specified by the index is asurrogate, the surrogatevalue is returned.

      Specified by:
      charAt in interface CharSequence
      Parameters:
      index - the index of thechar value.
      Returns:
      thechar value at the specified index of this string. The firstchar value is at index0.
      Throws:
      IndexOutOfBoundsException - if theindex argument is negative or not less than the length of this string.

    • codePointAt

      public int codePointAt(int index)
      Returns the character (Unicode code point) at the specifiedindex. The index refers tochar values(Unicode code units) and ranges from0 tolength() - 1.

      If thechar value specified at the given indexis in the high-surrogate range, the following index is lessthan the length of thisString, and thechar value at the following index is in thelow-surrogate range, then the supplementary code pointcorresponding to this surrogate pair is returned. Otherwise,thechar value at the given index is returned.

      Parameters:
      index - the index to thechar values
      Returns:
      the code point value of the character at theindex
      Throws:
      IndexOutOfBoundsException - if theindex argument is negative or not less than the length of this string.
      Since:
      1.5

    • codePointBefore

      public int codePointBefore(int index)
      Returns the character (Unicode code point) before the specifiedindex. The index refers tochar values(Unicode code units) and ranges from1 tolength.

      If thechar value at(index - 1)is in the low-surrogate range,(index - 2) is notnegative, and thechar value at(index -2) is in the high-surrogate range, then thesupplementary code point value of the surrogate pair isreturned. If thechar value atindex -1 is an unpaired low-surrogate or a high-surrogate, thesurrogate value is returned.

      Parameters:
      index - the index following the code point that should be returned
      Returns:
      the Unicode code point value before the given index.
      Throws:
      IndexOutOfBoundsException - if theindex argument is less than 1 or greater than the length of this string.
      Since:
      1.5

    • codePointCount

      public int codePointCount(int beginIndex, int endIndex)
      Returns the number of Unicode code points in the specified textrange of thisString. The text range begins at thespecifiedbeginIndex and extends to thechar at indexendIndex - 1. Thus thelength (inchars) of the text range isendIndex-beginIndex. Unpaired surrogates withinthe text range count as one code point each.
      Parameters:
      beginIndex - the index to the firstchar ofthe text range.
      endIndex - the index after the lastchar ofthe text range.
      Returns:
      the number of Unicode code points in the specified textrange
      Throws:
      IndexOutOfBoundsException - if thebeginIndex is negative, orendIndexis larger than the length of thisString, orbeginIndex is larger thanendIndex.
      Since:
      1.5

    • offsetByCodePoints

      public int offsetByCodePoints(int index, int codePointOffset)
      Returns the index within thisString that isoffset from the givenindex bycodePointOffset code points. Unpaired surrogateswithin the text range given byindex andcodePointOffset count as one code point each.
      Parameters:
      index - the index to be offset
      codePointOffset - the offset in code points
      Returns:
      the index within thisString
      Throws:
      IndexOutOfBoundsException - ifindex is negative or larger than the length of thisString, or ifcodePointOffset is positive and the substring starting withindex has fewer thancodePointOffset code points, or ifcodePointOffset is negative and the substring beforeindex has fewer than the absolute value ofcodePointOffset code points.
      Since:
      1.5

    • getChars

      public void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
      Copies characters from this sequence into the given destination array.The first character to be copied is at indexsrcBegin; the lastcharacter to be copied is at indexsrcEnd-1. The total number ofcharacters to be copied issrcEnd-srcBegin. Thecharacters are copied into the subarray ofdst startingat indexdstBegin and ending at index:
      dstbegin + (srcEnd-srcBegin) - 1
      Specified by:
      getChars in interface CharSequence
      Parameters:
      srcBegin - start copying at this offset.
      srcEnd - stop copying at this offset.
      dst - the array to copy the data into.
      dstBegin - offset intodst.
      Throws:
      IndexOutOfBoundsException - if any of the following is true:
      • srcBegin is negative
      • dstBegin is negative
      • thesrcBegin argument is greater than thesrcEnd argument.
      • srcEnd is greater thanthis.length().
      • dstBegin+srcEnd-srcBegin is greater thandst.length

    • getBytes

      @Deprecated(since="1.1")public void getBytes(int srcBegin, int srcEnd, byte[] dst, int dstBegin)
      Deprecated.
      This method does not properly convert characters intobytes. As of JDK 1.1, the preferred way to do this is via thegetBytes() method, which uses thedefault charset.
      Copies characters from this string into the destination byte array. Eachbyte receives the 8 low-order bits of the corresponding character. Theeight high-order bits of each character are not copied and do notparticipate in the transfer in any way.

      The first character to be copied is at indexsrcBegin; thelast character to be copied is at indexsrcEnd-1. The totalnumber of characters to be copied issrcEnd-srcBegin. Thecharacters, converted to bytes, are copied into the subarray ofdst starting at indexdstBegin and ending at index:

          dstBegin + (srcEnd-srcBegin) - 1

      Parameters:
      srcBegin - Index of the first character in the string to copy
      srcEnd - Index after the last character in the string to copy
      dst - The destination array
      dstBegin - The start offset in the destination array
      Throws:
      IndexOutOfBoundsException - If any of the following is true:
      • srcBegin is negative
      • srcBegin is greater thansrcEnd
      • srcEnd is greater than the length of this String
      • dstBegin is negative
      • dstBegin+(srcEnd-srcBegin) is larger than dst.length

    • getBytes

      public byte[] getBytes(String charsetName) throwsUnsupportedEncodingException
      Encodes thisString into a sequence of bytes using the namedcharset, storing the result into a new byte array.

      The behavior of this method when this string cannot be encoded inthe given charset is unspecified. TheCharsetEncoder class should be used when more controlover the encoding process is required.

      Parameters:
      charsetName - The name of a supportedcharset
      Returns:
      The resultant byte array
      Throws:
      UnsupportedEncodingException - If the named charset is not supported
      Since:
      1.1

    • getBytes

      public byte[] getBytes(Charset charset)
      Encodes thisString into a sequence of bytes using the givencharset, storing the result into anew byte array.

      This method always replaces malformed-input and unmappable-charactersequences with this charset's default replacement byte array. TheCharsetEncoder class should be used when morecontrol over the encoding process is required.

      Parameters:
      charset - TheCharset to be used to encode theString
      Returns:
      The resultant byte array
      Since:
      1.6

    • getBytes

      public byte[] getBytes()
      Encodes thisString into a sequence of bytes using thedefault charset, storing the resultinto a new byte array.

      The behavior of this method when this string cannot be encoded inthe default charset is unspecified. TheCharsetEncoder class should be used when more controlover the encoding process is required.

      Returns:
      The resultant byte array
      Since:
      1.1

    • equals

      public boolean equals(Object anObject)
      Compares this string to the specified object. The result istrue if and only if the argument is notnull and is aString object that represents the same sequence of characters as thisobject.

      For finer-grained String comparison, refer toCollator.

      Overrides:
      equals in class Object
      Parameters:
      anObject - The object to compare thisString against
      Returns:
      true if the given object represents aString equivalent to this string,false otherwise
      See Also:

    • contentEquals

      public boolean contentEquals(StringBuffer sb)
      Compares this string to the specifiedStringBuffer. The resultistrue if and only if thisString represents the samesequence of characters as the specifiedStringBuffer. This methodsynchronizes on theStringBuffer.

      For finer-grained String comparison, refer toCollator.

      Parameters:
      sb - TheStringBuffer to compare thisString against
      Returns:
      true if thisString represents the same sequence of characters as the specifiedStringBuffer,false otherwise
      Since:
      1.4

    • contentEquals

      public boolean contentEquals(CharSequence cs)
      Compares this string to the specifiedCharSequence. Theresult istrue if and only if thisString represents thesame sequence of char values as the specified sequence. Note that if theCharSequence is aStringBuffer then the methodsynchronizes on it.

      For finer-grained String comparison, refer toCollator.

      Parameters:
      cs - The sequence to compare thisString against
      Returns:
      true if thisString represents the same sequence of char values as the specified sequence, false otherwise
      Since:
      1.5

    • equalsIgnoreCase

      public boolean equalsIgnoreCase(String anotherString)
      Compares thisString to anotherString, ignoring caseconsiderations. Two strings are considered equal ignoring case if theyare of the same length and corresponding Unicode code points in the twostrings are equal ignoring case.

      Two Unicode code points are considered the sameignoring case if at least one of the following is true:

      • The two Unicode code points are the same (as compared by the== operator)
      • CallingCharacter.toLowerCase(Character.toUpperCase(int)) on each Unicode code point produces the same result

      Note that this method doesnot take locale into account, andwill result in unsatisfactory results for certain locales. TheCollator class provides locale-sensitive comparison.

      Parameters:
      anotherString - TheString to compare thisString against
      Returns:
      true if the argument is notnull and it represents an equivalentString ignoring case; false otherwise
      See Also:

    • compareTo

      public int compareTo(String anotherString)
      Compares two strings lexicographically.The comparison is based on the Unicode value of each character inthe strings. The character sequence represented by thisString object is compared lexicographically to thecharacter sequence represented by the argument string. The result isa negative integer if thisString objectlexicographically precedes the argument string. The result is apositive integer if thisString object lexicographicallyfollows the argument string. The result is zero if the stringsare equal;compareTo returns0 exactly whentheequals(Object) method would returntrue.

      This is the definition of lexicographic ordering. If two strings aredifferent, then either they have different characters at some indexthat is a valid index for both strings, or their lengths are different,or both. If they have different characters at one or more indexpositions, letk be the smallest such index; then the stringwhose character at positionk has the smaller value, asdetermined by using the< operator, lexicographically precedes theother string. In this case,compareTo returns thedifference of the two character values at positionk inthe two string -- that is, the value:

      this.charAt(k)-anotherString.charAt(k)
      If there is no index position at which they differ, then the shorterstring lexicographically precedes the longer string. In this case,compareTo returns the difference of the lengths of thestrings -- that is, the value:
      this.length()-anotherString.length()

      For finer-grained String comparison, refer toCollator.

      Specified by:
      compareTo in interface Comparable<String>
      Parameters:
      anotherString - theString to be compared.
      Returns:
      the value0 if the argument string is equal to this string; a value less than0 if this string is lexicographically less than the string argument; and a value greater than0 if this string is lexicographically greater than the string argument.

    • compareToIgnoreCase

      public int compareToIgnoreCase(String str)
      Compares two strings lexicographically, ignoring casedifferences. This method returns an integer whose sign is that ofcallingcompareTo with case folded versions of the stringswhere case differences have been eliminated by callingCharacter.toLowerCase(Character.toUpperCase(int)) oneach Unicode code point.

      Note that this method doesnot take locale into account,and will result in an unsatisfactory ordering for certain locales.TheCollator class provides locale-sensitive comparison.

      Parameters:
      str - theString to be compared.
      Returns:
      a negative integer, zero, or a positive integer as the specified String is greater than, equal to, or less than this String, ignoring case considerations.
      Since:
      1.2
      See Also:

    • regionMatches

      public boolean regionMatches(int toffset,String other, int ooffset, int len)
      Tests if two string regions are equal.

      A substring of thisString object is compared to a substringof the argument other. The result is true if these substringsrepresent identical character sequences. The substring of thisString object to be compared begins at indextoffsetand has lengthlen. The substring of other to be comparedbegins at indexooffset and has lengthlen. Theresult isfalse if and only if at least one of the followingis true:

      • toffset is negative.
      • ooffset is negative.
      • toffset+len is greater than the length of thisString object.
      • ooffset+len is greater than the length of the otherargument.
      • There is some nonnegative integerk less thanlensuch that:this.charAt(toffset +k) != other.charAt(ooffset +k)

      Note that this method doesnot take locale into account. TheCollator class provides locale-sensitive comparison.

      Parameters:
      toffset - the starting offset of the subregion in this string.
      other - the string argument.
      ooffset - the starting offset of the subregion in the string argument.
      len - the number of characters to compare.
      Returns:
      true if the specified subregion of this string exactly matches the specified subregion of the string argument;false otherwise.

    • regionMatches

      public boolean regionMatches(boolean ignoreCase, int toffset,String other, int ooffset, int len)
      Tests if two string regions are equal.

      A substring of thisString object is compared to a substringof the argumentother. The result istrue if thesesubstrings represent Unicode code point sequences that are the same,ignoring case if and only ifignoreCase is true.The sequencestsequence andosequence are compared,wheretsequence is the sequence produced as if by callingthis.substring(toffset, toffset + len).codePoints() andosequence is the sequence produced as if by callingother.substring(ooffset, ooffset + len).codePoints().The result istrue if and only if all of the followingare true:

      • toffset is non-negative.
      • ooffset is non-negative.
      • toffset+len is less than or equal to the length of thisString object.
      • ooffset+len is less than or equal to the length of the otherargument.
      • ifignoreCase isfalse, all pairs of corresponding Unicodecode points are equal integer values; or ifignoreCase istrue,Character.toLowerCase(Character.toUpperCase(int)) on all pairs of Unicode code pointsresults in equal integer values.

      Note that this method doesnot take locale into account,and will result in unsatisfactory results for certain locales whenignoreCase istrue. TheCollator classprovides locale-sensitive comparison.

      Parameters:
      ignoreCase - iftrue, ignore case when comparing characters.
      toffset - the starting offset of the subregion in this string.
      other - the string argument.
      ooffset - the starting offset of the subregion in the string argument.
      len - the number of characters (Unicode code units - 16bitchar value) to compare.
      Returns:
      true if the specified subregion of this string matches the specified subregion of the string argument;false otherwise. Whether the matching is exact or case insensitive depends on theignoreCase argument.
      See Also:

    • startsWith

      public boolean startsWith(String prefix, int toffset)
      Tests if the substring of this string beginning at thespecified index starts with the specified prefix.
      Parameters:
      prefix - the prefix.
      toffset - where to begin looking in this string.
      Returns:
      true if the character sequence represented by the argument is a prefix of the substring of this object starting at indextoffset;false otherwise. The result isfalse iftoffset is negative or greater than the length of thisString object; otherwise the result is the same as the result of the expression
               this.substring(toffset).startsWith(prefix)

    • startsWith

      public boolean startsWith(String prefix)
      Tests if this string starts with the specified prefix.
      Parameters:
      prefix - the prefix.
      Returns:
      true if the character sequence represented by the argument is a prefix of the character sequence represented by this string;false otherwise. Note also thattrue will be returned if the argument is an empty string or is equal to thisString object as determined by theequals(Object) method.
      Since:
      1.0

    • endsWith

      public boolean endsWith(String suffix)
      Tests if this string ends with the specified suffix.
      Parameters:
      suffix - the suffix.
      Returns:
      true if the character sequence represented by the argument is a suffix of the character sequence represented by this object;false otherwise. Note that the result will betrue if the argument is the empty string or is equal to thisString object as determined by theequals(Object) method.

    • hashCode

      public int hashCode()
      Returns a hash code for this string. The hash code for aString object is computed as
      s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]
      usingint arithmetic, wheres[i] is theith character of the string,n is the length ofthe string, and^ indicates exponentiation.(The hash value of the empty string is zero.)
      Overrides:
      hashCode in class Object
      Returns:
      a hash code value for this object.
      See Also:

    • indexOf

      public int indexOf(int ch)
      Returns the index within this string of the first occurrence ofthe specified character. If a character with valuech occurs in the character sequence represented bythisString object, then the index (in Unicodecode units) of the first such occurrence is returned. Forvalues ofch in the range from 0 to 0xFFFF(inclusive), this is the smallest valuek such that:
      this.charAt(k) == ch
      is true. For other values ofch, it is thesmallest valuek such that:
      this.codePointAt(k) == ch
      is true. In either case, if no such character occurs in thisstring, then-1 is returned.
      Parameters:
      ch - a character (Unicode code point).
      Returns:
      the index of the first occurrence of the character in the character sequence represented by this object, or-1 if the character does not occur.

    • indexOf

      public int indexOf(int ch, int fromIndex)
      Returns the index within this string of the first occurrence of thespecified character, starting the search at the specified index.

      If a character with valuech occurs in thecharacter sequence represented by thisStringobject at an index no smaller thanfromIndex, thenthe index of the first such occurrence is returned. For valuesofch in the range from 0 to 0xFFFF (inclusive),this is the smallest valuek such that:

      (this.charAt(k) == ch)&& (k >= fromIndex)
      is true. For other values ofch, it is thesmallest valuek such that:
      (this.codePointAt(k) == ch)&& (k >= fromIndex)
      is true. In either case, if no such character occurs in thisstring at or after positionfromIndex, then-1 is returned.

      There is no restriction on the value offromIndex. If itis negative, it has the same effect as if it were zero: this entirestring may be searched. If it is greater than the length of thisstring, it has the same effect as if it were equal to the length ofthis string:-1 is returned.

      All indices are specified inchar values(Unicode code units).

      API Note:
      Unlikesubstring(int), for example, this method does not throwan exception whenfromIndex is outside the valid range.Rather, it returns -1 whenfromIndex is larger than the length ofthe string.This result is, by itself, indistinguishable from a genuine absence ofch in the string.If stricter behavior is needed,indexOf(int, int, int)should be considered instead.On aStrings, for example,s.indexOf(ch, fromIndex, s.length()) would throw iffromIndex were larger than the string length, or were negative.
      Parameters:
      ch - a character (Unicode code point).
      fromIndex - the index to start the search from.
      Returns:
      the index of the first occurrence of the character in the character sequence represented by this object that is greater than or equal tofromIndex, or-1 if the character does not occur.

    • indexOf

      public int indexOf(int ch, int beginIndex, int endIndex)
      Returns the index within this string of the first occurrence of thespecified character, starting the search atbeginIndex andstopping beforeendIndex.

      If a character with valuech occurs in thecharacter sequence represented by thisStringobject at an index no smaller thanbeginIndex but smaller thanendIndex, thenthe index of the first such occurrence is returned. For valuesofch in the range from 0 to 0xFFFF (inclusive),this is the smallest valuek such that:

      (this.charAt(k) == ch) && (beginIndex <=k < endIndex)
      is true. For other values ofch, it is thesmallest valuek such that:
      (this.codePointAt(k) == ch) && (beginIndex <=k < endIndex)
      is true. In either case, if no such character occurs in thisstring at or after positionbeginIndex and before positionendIndex, then-1 is returned.

      All indices are specified inchar values(Unicode code units).

      Parameters:
      ch - a character (Unicode code point).
      beginIndex - the index to start the search from (included).
      endIndex - the index to stop the search at (excluded).
      Returns:
      the index of the first occurrence of the character in the character sequence represented by this object that is greater than or equal tobeginIndex and less thanendIndex, or-1 if the character does not occur.
      Throws:
      StringIndexOutOfBoundsException - ifbeginIndex is negative, orendIndex is larger than the length of thisString object, orbeginIndex is larger thanendIndex.
      Since:
      21

    • lastIndexOf

      public int lastIndexOf(int ch)
      Returns the index within this string of the last occurrence ofthe specified character. For values ofch in therange from 0 to 0xFFFF (inclusive), the index (in Unicode codeunits) returned is the largest valuek such that:
      this.charAt(k) == ch
      is true. For other values ofch, it is thelargest valuek such that:
      this.codePointAt(k) == ch
      is true. In either case, if no such character occurs in thisstring, then-1 is returned. TheString is searched backwards starting at the lastcharacter.
      Parameters:
      ch - a character (Unicode code point).
      Returns:
      the index of the last occurrence of the character in the character sequence represented by this object, or-1 if the character does not occur.

    • lastIndexOf

      public int lastIndexOf(int ch, int fromIndex)
      Returns the index within this string of the last occurrence ofthe specified character, searching backward starting at thespecified index. For values ofch in the rangefrom 0 to 0xFFFF (inclusive), the index returned is the largestvaluek such that:
      (this.charAt(k) == ch)&& (k <= fromIndex)
      is true. For other values ofch, it is thelargest valuek such that:
      (this.codePointAt(k) == ch)&& (k <= fromIndex)
      is true. In either case, if no such character occurs in thisstring at or before positionfromIndex, then-1 is returned.

      All indices are specified inchar values(Unicode code units).

      Parameters:
      ch - a character (Unicode code point).
      fromIndex - the index to start the search from. There is no restriction on the value offromIndex. If it is greater than or equal to the length of this string, it has the same effect as if it were equal to one less than the length of this string: this entire string may be searched. If it is negative, it has the same effect as if it were -1: -1 is returned.
      Returns:
      the index of the last occurrence of the character in the character sequence represented by this object that is less than or equal tofromIndex, or-1 if the character does not occur before that point.

    • indexOf

      public int indexOf(String str)
      Returns the index within this string of the first occurrence of thespecified substring.

      The returned index is the smallest valuek for which:

      this.startsWith(str, k)
      If no such value ofk exists, then-1 is returned.

      Parameters:
      str - the substring to search for.
      Returns:
      the index of the first occurrence of the specified substring, or-1 if there is no such occurrence.

    • indexOf

      public int indexOf(String str, int fromIndex)
      Returns the index within this string of the first occurrence of thespecified substring, starting at the specified index.

      The returned index is the smallest valuek for which:

          k >= Math.min(fromIndex, this.length()) &&                  this.startsWith(str, k)
      If no such value ofk exists, then-1 is returned.

      API Note:
      Unlikesubstring(int), for example, this method does not throwan exception whenfromIndex is outside the valid range.Rather, it returns -1 whenfromIndex is larger than the length ofthe string.This result is, by itself, indistinguishable from a genuine absence ofstr in the string.If stricter behavior is needed,indexOf(String, int, int)should be considered instead.OnStrings and a non-emptystr, for example,s.indexOf(str, fromIndex, s.length()) would throw iffromIndex were larger than the string length, or were negative.
      Parameters:
      str - the substring to search for.
      fromIndex - the index from which to start the search.
      Returns:
      the index of the first occurrence of the specified substring, starting at the specified index, or-1 if there is no such occurrence.

    • indexOf

      public int indexOf(String str, int beginIndex, int endIndex)
      Returns the index of the first occurrence of the specified substringwithin the specified index range ofthis string.

      This method returns the same result as the one of the invocation

          s.substring(beginIndex, endIndex).indexOf(str) + beginIndex
      if the index returned byindexOf(String) is non-negative,and returns -1 otherwise.(No substring is instantiated, though.)

      Parameters:
      str - the substring to search for.
      beginIndex - the index to start the search from (included).
      endIndex - the index to stop the search at (excluded).
      Returns:
      the index of the first occurrence of the specified substring within the specified index range, or-1 if there is no such occurrence.
      Throws:
      StringIndexOutOfBoundsException - ifbeginIndex is negative, orendIndex is larger than the length of thisString object, orbeginIndex is larger thanendIndex.
      Since:
      21

    • lastIndexOf

      public int lastIndexOf(String str)
      Returns the index within this string of the last occurrence of thespecified substring. The last occurrence of the empty string ""is considered to occur at the index valuethis.length().

      The returned index is the largest valuek for which:

      this.startsWith(str, k)
      If no such value ofk exists, then-1 is returned.

      Parameters:
      str - the substring to search for.
      Returns:
      the index of the last occurrence of the specified substring, or-1 if there is no such occurrence.

    • lastIndexOf

      public int lastIndexOf(String str, int fromIndex)
      Returns the index within this string of the last occurrence of thespecified substring, searching backward starting at the specified index.

      The returned index is the largest valuek for which:

          k <= Math.min(fromIndex, this.length()) &&                  this.startsWith(str, k)
      If no such value ofk exists, then-1 is returned.

      Parameters:
      str - the substring to search for.
      fromIndex - the index to start the search from.
      Returns:
      the index of the last occurrence of the specified substring, searching backward from the specified index, or-1 if there is no such occurrence.

    • substring

      public String substring(int beginIndex)
      Returns a string that is a substring of this string. Thesubstring begins with the character at the specified index andextends to the end of this string.

      Examples:

      "unhappy".substring(2) returns "happy""Harbison".substring(3) returns "bison""emptiness".substring(9) returns "" (an empty string)

      Parameters:
      beginIndex - the beginning index, inclusive.
      Returns:
      the specified substring.
      Throws:
      IndexOutOfBoundsException - ifbeginIndex is negative or larger than the length of thisString object.

    • substring

      public String substring(int beginIndex, int endIndex)
      Returns a string that is a substring of this string. Thesubstring begins at the specifiedbeginIndex andextends to the character at indexendIndex - 1.Thus the length of the substring isendIndex-beginIndex.

      Examples:

      "hamburger".substring(4, 8) returns "urge""smiles".substring(1, 5) returns "mile"

      Parameters:
      beginIndex - the beginning index, inclusive.
      endIndex - the ending index, exclusive.
      Returns:
      the specified substring.
      Throws:
      IndexOutOfBoundsException - if thebeginIndex is negative, orendIndex is larger than the length of thisString object, orbeginIndex is larger thanendIndex.

    • subSequence

      public CharSequence subSequence(int beginIndex, int endIndex)
      Returns a character sequence that is a subsequence of this sequence.

      An invocation of this method of the form

      str.subSequence(begin, end)
      behaves in exactly the same way as the invocation
      str.substring(begin, end)

      Specified by:
      subSequence in interface CharSequence
      API Note:
      This method is defined so that theString class can implementtheCharSequence interface.
      Parameters:
      beginIndex - the begin index, inclusive.
      endIndex - the end index, exclusive.
      Returns:
      the specified subsequence.
      Throws:
      IndexOutOfBoundsException - ifbeginIndex orendIndex is negative, ifendIndex is greater thanlength(), or ifbeginIndex is greater thanendIndex
      Since:
      1.4

    • concat

      public String concat(String str)
      Concatenates the specified string to the end of this string.

      If the length of the argument string is0, then thisString object is returned. Otherwise, aString object is returned that represents a charactersequence that is the concatenation of the character sequencerepresented by thisString object and the charactersequence represented by the argument string.

      Examples:

      "cares".concat("s") returns "caress""to".concat("get").concat("her") returns "together"

      Parameters:
      str - theString that is concatenated to the end of thisString.
      Returns:
      a string that represents the concatenation of this object's characters followed by the string argument's characters.

    • replace

      public String replace(char oldChar, char newChar)
      Returns a string resulting from replacing all occurrences ofoldChar in this string withnewChar.

      If the characteroldChar does not occur in thecharacter sequence represented by thisString object,then a reference to thisString object is returned.Otherwise, aString object is returned thatrepresents a character sequence identical to the character sequencerepresented by thisString object, except that everyoccurrence ofoldChar is replaced by an occurrenceofnewChar.

      Examples:

      "mesquite in your cellar".replace('e', 'o')        returns "mosquito in your collar""the war of baronets".replace('r', 'y')        returns "the way of bayonets""sparring with a purple porpoise".replace('p', 't')        returns "starring with a turtle tortoise""JonL".replace('q', 'x') returns "JonL" (no change)

      Parameters:
      oldChar - the old character.
      newChar - the new character.
      Returns:
      a string derived from this string by replacing every occurrence ofoldChar withnewChar.

    • matches

      public boolean matches(String regex)
      Tells whether or not this string matches the givenregular expression.

      An invocation of this method of the formstr.matches(regex) yields exactly thesame result as the expression

      Pattern.matches(regex,str)

      Parameters:
      regex - the regular expression to which this string is to be matched
      Returns:
      true if, and only if, this string matches the given regular expression
      Throws:
      PatternSyntaxException - if the regular expression's syntax is invalid
      Since:
      1.4
      See Also:

    • contains

      public boolean contains(CharSequence s)
      Returns true if and only if this string contains the specifiedsequence of char values.
      Parameters:
      s - the sequence to search for
      Returns:
      true if this string containss, false otherwise
      Since:
      1.5

    • replaceFirst

      public String replaceFirst(String regex,String replacement)
      Replaces the first substring of this string that matches the givenregular expression with the given replacement.

      An invocation of this method of the formstr.replaceFirst(regex,repl) yields exactly the same result as the expression

      Pattern.compile(regex).matcher(str).replaceFirst(repl)

      Note that backslashes (\) and dollar signs ($) in the replacement string may cause the results to be different than if it were being treated as a literal replacement string; seeMatcher.replaceFirst(String). UseMatcher.quoteReplacement(String) to suppress the special meaning of these characters, if desired.

      Parameters:
      regex - the regular expression to which this string is to be matched
      replacement - the string to be substituted for the first match
      Returns:
      The resultingString
      Throws:
      PatternSyntaxException - if the regular expression's syntax is invalid
      Since:
      1.4
      See Also:

    • replaceAll

      public String replaceAll(String regex,String replacement)
      Replaces each substring of this string that matches the givenregular expression with the given replacement.

      An invocation of this method of the formstr.replaceAll(regex,repl) yields exactly the same result as the expression

      Pattern.compile(regex).matcher(str).replaceAll(repl)

      Note that backslashes (\) and dollar signs ($) in the replacement string may cause the results to be different than if it were being treated as a literal replacement string; seeMatcher.replaceAll. UseMatcher.quoteReplacement(String) to suppress the special meaning of these characters, if desired.

      Parameters:
      regex - the regular expression to which this string is to be matched
      replacement - the string to be substituted for each match
      Returns:
      The resultingString
      Throws:
      PatternSyntaxException - if the regular expression's syntax is invalid
      Since:
      1.4
      See Also:

    • replace

      public String replace(CharSequence target,CharSequence replacement)
      Replaces each substring of this string that matches the literal targetsequence with the specified literal replacement sequence. Thereplacement proceeds from the beginning of the string to the end, forexample, replacing "aa" with "b" in the string "aaa" will result in"ba" rather than "ab".
      Parameters:
      target - The sequence of char values to be replaced
      replacement - The replacement sequence of char values
      Returns:
      The resulting string
      Since:
      1.5

    • split

      public String[] split(String regex, int limit)
      Splits this string around matches of the givenregular expression.

      The array returned by this method contains each substring of thisstring that is terminated by another substring that matches the givenexpression or is terminated by the end of the string. The substrings inthe array are in the order in which they occur in this string. If theexpression does not match any part of the input then the resulting arrayhas just one element, namely this string.

      When there is a positive-width match at the beginning of thisstring then an empty leading substring is included at the beginningof the resulting array. A zero-width match at the beginning howevernever produces such empty leading substring.

      Thelimit parameter controls the number of times thepattern is applied and therefore affects the length of the resultingarray.

      • If thelimit is positive then the pattern will be applied at mostlimit - 1 times, the array's length will be no greater thanlimit, and the array's last entry will contain all input beyond the last matched delimiter.

      • If thelimit is zero then the pattern will be applied as many times as possible, the array can have any length, and trailing empty strings will be discarded.

      • If thelimit is negative then the pattern will be applied as many times as possible and the array can have any length.

      The string"boo:and:foo", for example, yields thefollowing results with these parameters:

      Split example showing regex, limit, and result
      RegexLimitResult
      :2{ "boo", "and:foo" }
      5{ "boo", "and", "foo" }
      -2{ "boo", "and", "foo" }
      o5{ "b", "", ":and:f", "", "" }
      -2{ "b", "", ":and:f", "", "" }
      0{ "b", "", ":and:f" }

      An invocation of this method of the formstr.split(regex, n)yields the same result as the expression

      Pattern.compile(regex).split(str, n)

      Parameters:
      regex - the delimiting regular expression
      limit - the result threshold, as described above
      Returns:
      the array of strings computed by splitting this string around matches of the given regular expression
      Throws:
      PatternSyntaxException - if the regular expression's syntax is invalid
      Since:
      1.4
      See Also:

    • splitWithDelimiters

      public String[] splitWithDelimiters(String regex, int limit)
      Splits this string around matches of the given regular expression andreturns both the strings and the matching delimiters.

      The array returned by this method contains each substring of thisstring that is terminated by another substring that matches the givenexpression or is terminated by the end of the string.Each substring is immediately followed by the subsequence (the delimiter)that matches the given expression,except for the lastsubstring, which is not followed by anything.The substrings in the array and the delimiters are in the order in whichthey occur in the input.If the expression does not match any part of the input then the resultingarray has just one element, namely this string.

      When there is a positive-width match at the beginning of thisstring then an empty leading substring is included at the beginningof the resulting array. A zero-width match at the beginning howevernever produces such empty leading substring nor the empty delimiter.

      Thelimit parameter controls the number of times thepattern is applied and therefore affects the length of the resultingarray.

      • If thelimit is positive then the pattern will be applied at mostlimit - 1 times, the array's length will be no greater than 2 ×limit - 1, and the array's last entry will contain all input beyond the last matched delimiter.
      • If thelimit is zero then the pattern will be applied as many times as possible, the array can have any length, and trailing empty strings will be discarded.
      • If thelimit is negative then the pattern will be applied as many times as possible and the array can have any length.

      The input"boo:::and::foo", for example, yields the followingresults with these parameters:

      Split example showing regex, limit, and result
      RegexLimitResult
      :+2{ "boo", ":::", "and::foo" }
      5{ "boo", ":::", "and", "::", "foo" }
      -1{ "boo", ":::", "and", "::", "foo" }
      o5{ "b", "o", "", "o", ":::and::f", "o", "", "o", "" }
      -1{ "b", "o", "", "o", ":::and::f", "o", "", "o", "" }
      0{ "b", "o", "", "o", ":::and::f", "o", "", "o" }

      API Note:
      An invocation of this method of the formstr.splitWithDelimiters(regex, n)yields the same result as the expression
      Pattern.compile(regex).splitWithDelimiters(str, n)
      Parameters:
      regex - the delimiting regular expression
      limit - the result threshold, as described above
      Returns:
      the array of strings computed by splitting this string around matches of the given regular expression, alternating substrings and matching delimiters
      Since:
      21

    • split

      public String[] split(String regex)
      Splits this string around matches of the givenregular expression.

      This method works as if by invoking the two-argumentsplit method with the given expression and a limitargument of zero. Trailing empty strings are therefore not included inthe resulting array.

      The string"boo:and:foo", for example, yields the followingresults with these expressions:

      Split examples showing regex and result
      RegexResult
      :{ "boo", "and", "foo" }
      o{ "b", "", ":and:f" }

      Parameters:
      regex - the delimiting regular expression
      Returns:
      the array of strings computed by splitting this string around matches of the given regular expression
      Throws:
      PatternSyntaxException - if the regular expression's syntax is invalid
      Since:
      1.4
      See Also:

    • join

      public static String join(CharSequence delimiter,CharSequence... elements)
      Returns a new String composed of copies of theCharSequence elements joined together with a copy ofthe specifieddelimiter.
      For example,
          String message = String.join("-", "Java", "is", "cool");    // message returned is: "Java-is-cool"
      Note that if an element is null, then"null" is added.
      Parameters:
      delimiter - the delimiter that separates each element
      elements - the elements to join together.
      Returns:
      a newString that is composed of theelements separated by thedelimiter
      Throws:
      NullPointerException - Ifdelimiter orelements isnull
      Since:
      1.8
      See Also:

    • join

      public static String join(CharSequence delimiter,Iterable<? extendsCharSequence> elements)
      Returns a newString composed of copies of theCharSequence elements joined together with a copy of thespecifieddelimiter.
      For example,
          List<String> strings = List.of("Java", "is", "cool");    String message = String.join(" ", strings);    // message returned is: "Java is cool"    Set<String> strings =        new LinkedHashSet<>(List.of("Java", "is", "very", "cool"));    String message = String.join("-", strings);    // message returned is: "Java-is-very-cool"
      Note that if an individual element isnull, then"null" is added.
      Parameters:
      delimiter - a sequence of characters that is used to separate each of theelements in the resultingString
      elements - anIterable that will have itselements joined together.
      Returns:
      a newString that is composed from theelements argument
      Throws:
      NullPointerException - Ifdelimiter orelements isnull
      Since:
      1.8
      See Also:

    • toLowerCase

      public String toLowerCase(Locale locale)
      Converts all of the characters in thisString to lowercase using the rules of the givenLocale. Case mapping is basedon the Unicode Standard version specified by theCharacterclass. Since case mappings are not always 1:1 char mappings, the resultingStringand thisString may differ in length.

      Examples of lowercase mappings are in the following table:

      Lowercase mapping examples showing language code of locale, upper case, lower case, and description
      Language Code of LocaleUpper CaseLower CaseDescription
      tr (Turkish)\u0130\u0069capital letter I with dot above -> small letter i
      tr (Turkish)\u0049\u0131capital letter I -> small letter dotless i
      (all)French Friesfrench frieslowercased all chars in String
      (all) ΙΧΘΥΣιχθυσlowercased all chars in String

      Parameters:
      locale - use the case transformation rules for this locale
      Returns:
      theString, converted to lowercase.
      Since:
      1.1
      See Also:

    • toLowerCase

      public String toLowerCase()
      Converts all of the characters in thisString to lowercase using the rules of the default locale. This method is equivalent totoLowerCase(Locale.getDefault()).
      API Note:
      This method is locale sensitive, and may produce unexpectedresults if used for strings that are intended to be interpreted localeindependently.Examples are programming language identifiers, protocol keys, and HTMLtags.For instance,"TITLE".toLowerCase() in a Turkish localereturns"t\u0131tle", where '\u0131' is theLATIN SMALL LETTER DOTLESS I character.To obtain correct results for locale insensitive strings, usetoLowerCase(Locale.ROOT).
      Returns:
      theString, converted to lowercase.
      See Also:

    • toUpperCase

      public String toUpperCase(Locale locale)
      Converts all of the characters in thisString to uppercase using the rules of the givenLocale. Case mapping is basedon the Unicode Standard version specified by theCharacterclass. Since case mappings are not always 1:1 char mappings, the resultingStringand thisString may differ in length.

      Examples of locale-sensitive and 1:M case mappings are in the following table:

      Examples of locale-sensitive and 1:M case mappings. Shows Language code of locale, lower case, upper case, and description.
      Language Code of LocaleLower CaseUpper CaseDescription
      tr (Turkish)\u0069\u0130small letter i -> capital letter I with dot above
      tr (Turkish)\u0131\u0049small letter dotless i -> capital letter I
      (all)\u00df\u0053 \u0053small letter sharp s -> two letters: SS
      (all)FahrvergnügenFAHRVERGNÜGEN

      Parameters:
      locale - use the case transformation rules for this locale
      Returns:
      theString, converted to uppercase.
      Since:
      1.1
      See Also:

    • toUpperCase

      public String toUpperCase()
      Converts all of the characters in thisString to uppercase using the rules of the default locale. This method is equivalent totoUpperCase(Locale.getDefault()).
      API Note:
      This method is locale sensitive, and may produce unexpectedresults if used for strings that are intended to be interpreted localeindependently.Examples are programming language identifiers, protocol keys, and HTMLtags.For instance,"title".toUpperCase() in a Turkish localereturns"T\u0130TLE", where '\u0130' is theLATIN CAPITAL LETTER I WITH DOT ABOVE character.To obtain correct results for locale insensitive strings, usetoUpperCase(Locale.ROOT).
      Returns:
      theString, converted to uppercase.
      See Also:

    • trim

      public String trim()
      Returns a string whose value is this string, with all leadingand trailing space removed, where space is definedas any character whose codepoint is less than or equal to'U+0020' (the space character).

      If thisString object represents an empty charactersequence, or the first and last characters of character sequencerepresented by thisString object both have codesthat are not space (as defined above), then areference to thisString object is returned.

      Otherwise, if all characters in this string are space (asdefined above), then aString object representing anempty string is returned.

      Otherwise, letk be the index of the first character in thestring whose code is not a space (as defined above) and letm be the index of the last character in the string whose codeis not a space (as defined above). AStringobject is returned, representing the substring of this string thatbegins with the character at indexk and ends with thecharacter at indexm-that is, the result ofthis.substring(k, m + 1).

      API Note:
      This method removes leading and trailing space characters and ASCII controlcharacters from the string. To remove characters using a Unicode-based definition ofwhite space, usestrip,stripIndent,stripLeading, orstripTrailing.
      Returns:
      a string whose value is this string, with all leading and trailing space removed, or this string if it has no leading or trailing space.

    • strip

      public String strip()
      Returns a string whose value is this string, with all leadingand trailingwhite spaceremoved.

      If thisString object represents an empty string,or if all code points in this string arewhite space, then an empty stringis returned.

      Otherwise, returns a substring of this string beginning with the firstcode point that is not awhite spaceup to and including the last code point that is not awhite space.

      This method may be used to stripwhite space fromthe beginning and end of a string.

      Returns:
      a string whose value is this string, with all leading and trailing white space removed
      Since:
      11
      See Also:

    • stripLeading

      public String stripLeading()
      Returns a string whose value is this string, with all leadingwhite space removed.

      If thisString object represents an empty string,or if all code points in this string arewhite space, then an empty stringis returned.

      Otherwise, returns a substring of this string beginning with the firstcode point that is not awhite spaceup to and including the last code point of this string.

      This method may be used to trimwhite space fromthe beginning of a string.

      Returns:
      a string whose value is this string, with all leading white space removed
      Since:
      11
      See Also:

    • stripTrailing

      public String stripTrailing()
      Returns a string whose value is this string, with all trailingwhite space removed.

      If thisString object represents an empty string,or if all characters in this string arewhite space, then an empty stringis returned.

      Otherwise, returns a substring of this string beginning with the firstcode point of this string up to and including the last code pointthat is not awhite space.

      This method may be used to trimwhite space fromthe end of a string.

      Returns:
      a string whose value is this string, with all trailing white space removed
      Since:
      11
      See Also:

    • isBlank

      public boolean isBlank()
      Returnstrue if the string isempty or containsonlywhite space codepoints,otherwisefalse.
      Returns:
      true if the string isempty or containsonlywhite space codepoints,otherwisefalse
      Since:
      11
      See Also:

    • lines

      public Stream<String> lines()
      Returns a stream of lines extracted from this string,separated by line terminators.

      Aline terminator is one of the following:a line feed character"\n" (U+000A),a carriage return character"\r" (U+000D),or a carriage return followed immediately by a line feed"\r\n" (U+000D U+000A).

      Aline is either a sequence of zero or more charactersfollowed by a line terminator, or it is a sequence of one ormore characters followed by the end of the string. Aline does not include the line terminator.

      The stream returned by this method contains the lines fromthis string in the order in which they occur.

      API Note:
      This definition ofline implies that an empty string has zero lines and that there is no empty line following a line terminator at the end of a string.
      Implementation Note:
      This method provides better performance than split("\R") by supplying elements lazily and by faster search of new line terminators.
      Returns:
      the stream of lines extracted from this string
      Since:
      11

    • indent

      public String indent(int n)
      Adjusts the indentation of each line of this string based on the value ofn, and normalizes line termination characters.

      This string is conceptually separated into lines usinglines(). Each line is then adjusted as described belowand then suffixed with a line feed"\n" (U+000A). The resultinglines are then concatenated and returned.

      Ifn > 0 thenn spaces (U+0020) are inserted at thebeginning of each line.

      Ifn < 0 then up tonwhite space characters are removedfrom the beginning of each line. If a given line does not containsufficient white space then all leadingwhite space characters are removed.Each white space character is treated as a single character. Inparticular, the tab character"\t" (U+0009) is considered asingle character; it is not expanded.

      Ifn == 0 then the line remains unchanged. However, lineterminators are still normalized.

      Parameters:
      n - number of leadingwhite space characters to add or remove
      Returns:
      string with indentation adjusted and line endings normalized
      Since:
      12
      See Also:

    • stripIndent

      public String stripIndent()
      Returns a string whose value is this string, with incidentalwhite space removed fromthe beginning and end of every line.

      Incidentalwhite spaceis often present in a text block to align the content with the openingdelimiter. For example, in the following code, dots represent incidentalwhite space:

      String html = """..............<html>..............    <body>..............        <p>Hello, world</p>..............    </body>..............</html>..............""";
      This method treats the incidentalwhite space as indentation to bestripped, producing a string that preserves the relative indentation ofthe content. Using | to visualize the start of each line of the string:
      |<html>|    <body>|        <p>Hello, world</p>|    </body>|</html>
      First, the individual lines of this string are extracted. Alineis a sequence of zero or more characters followed by either a lineterminator or the end of the string.If the string has at least one line terminator, the last line consistsof the characters between the last terminator and the end of the string.Otherwise, if the string has no terminators, the last line is the startof the string to the end of the string, in other words, the entirestring.A line does not include the line terminator.

      Then, theminimum indentation (min) is determined as follows:

      Themin value is the smallest of these counts.

      For eachnon-blank line,min leadingwhite space characters areremoved, and any trailingwhitespace characters are removed.Blank linesare replaced with the empty string.

      Finally, the lines are joined into a new string, using the LF character"\n" (U+000A) to separate lines.

      API Note:
      This method's primary purpose is to shift a block of lines as far aspossible to the left, while preserving relative indentation. Linesthat were indented the least will thus have no leadingwhite space.The result will have the same number of line terminators as this string.If this string ends with a line terminator then the result will endwith a line terminator.
      Implementation Requirements:
      This method treats allwhite spacecharacters as having equal width. As long as the indentation on everyline is consistently composed of the same character sequences, then theresult will be as described above.
      Returns:
      string with incidental indentation removed and line terminators normalized
      Since:
      15
      See Also:

    • translateEscapes

      public String translateEscapes()
      Returns a string whose value is this string, with escape sequencestranslated as if in a string literal.

      Escape sequences are translated as follows;

      Translation
      EscapeNameTranslation
      \bbackspaceU+0008
      \thorizontal tabU+0009
      \nline feedU+000A
      \fform feedU+000C
      \rcarriage returnU+000D
      \sspaceU+0020
      \"double quoteU+0022
      \'single quoteU+0027
      \\backslashU+005C
      \0 - \377octal escapecode point equivalents
      \<line-terminator>continuationdiscard

      Implementation Note:
      This method doesnot translate Unicode escapes such as "\u2022".Unicode escapes are translated by the Java compiler when reading input characters andare not part of the string literal specification.
      Returns:
      String with escape sequences translated.
      Throws:
      IllegalArgumentException - when an escape sequence is malformed.
      SeeJava Language Specification:
      3.10.7 Escape Sequences
      Since:
      15

    • transform

      public <R> R transform(Function<? superString, ? extends R> f)
      This method allows the application of a function tothisstring. The function should expect a single String argumentand produce anR result.

      Any exception thrown byf.apply() will be propagated to thecaller.

      Type Parameters:
      R - the type of the result
      Parameters:
      f - a function to apply
      Returns:
      the result of applying the function to this string
      Since:
      12
      See Also:

    • toString

      public String toString()
      This object (which is already a string!) is itself returned.
      Specified by:
      toString in interface CharSequence
      Overrides:
      toString in class Object
      Returns:
      the string itself.

    • chars

      public IntStream chars()
      Returns a stream ofint zero-extending thechar valuesfrom this sequence. Any char which maps to asurrogate code point is passed throughuninterpreted.
      Specified by:
      chars in interface CharSequence
      Returns:
      an IntStream of char values from this sequence
      Since:
      9

    • codePoints

      public IntStream codePoints()
      Returns a stream of code point values from this sequence. Any surrogatepairs encountered in the sequence are combined as if byCharacter.toCodePoint and the result is passedto the stream. Any other code units, including ordinary BMP characters,unpaired surrogates, and undefined code units, are zero-extended toint values which are then passed to the stream.
      Specified by:
      codePoints in interface CharSequence
      Returns:
      an IntStream of Unicode code points from this sequence
      Since:
      9

    • toCharArray

      public char[] toCharArray()
      Converts this string to a new character array.
      Returns:
      a newly allocated character array whose length is the length of this string and whose contents are initialized to contain the character sequence represented by this string.

    • format

      public static String format(String format,Object... args)
      Returns a formatted string using the specified format string andarguments.

      The locale always used is the one returned byLocale.getDefault(Locale.Category) withFORMAT category specified.

      Parameters:
      format - Aformat string
      args - Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined byThe Java Virtual Machine Specification. The behaviour on anull argument depends on theconversion.
      Returns:
      A formatted string
      Throws:
      IllegalFormatException - If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see theDetails section of the formatter class specification.
      Since:
      1.5
      See Also:

    • format

      public static String format(Locale l,String format,Object... args)
      Returns a formatted string using the specified locale, format string,and arguments.
      Parameters:
      l - Thelocale to apply during formatting. Ifl isnull then no localization is applied.
      format - Aformat string
      args - Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined byThe Java Virtual Machine Specification. The behaviour on anull argument depends on theconversion.
      Returns:
      A formatted string
      Throws:
      IllegalFormatException - If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see theDetails section of the formatter class specification
      Since:
      1.5
      See Also:

    • formatted

      public String formatted(Object... args)
      Formats using this string as the format string, and the suppliedarguments.
      Implementation Requirements:
      This method is equivalent toString.format(this, args).
      Parameters:
      args - Arguments referenced by the format specifiers in this string.
      Returns:
      A formatted string
      Since:
      15
      See Also:

    • valueOf

      public static String valueOf(Object obj)
      Returns the string representation of theObject argument.
      Parameters:
      obj - anObject.
      Returns:
      if the argument isnull, then a string equal to"null"; otherwise, the value ofobj.toString() is returned.
      See Also:

    • valueOf

      public static String valueOf(char[] data)
      Returns the string representation of thechar arrayargument. The contents of the character array are copied; subsequentmodification of the character array does not affect the returnedstring.

      The contents of the string are unspecified if the character arrayis modified during string construction.

      Parameters:
      data - the character array.
      Returns:
      aString that contains the characters of the character array.

    • valueOf

      public static String valueOf(char[] data, int offset, int count)
      Returns the string representation of a specific subarray of thechar array argument.

      Theoffset argument is the index of the firstcharacter of the subarray. Thecount argumentspecifies the length of the subarray. The contents of the subarrayare copied; subsequent modification of the character array does notaffect the returned string.

      The contents of the string are unspecified if the character arrayis modified during string construction.

      Parameters:
      data - the character array.
      offset - initial offset of the subarray.
      count - length of the subarray.
      Returns:
      aString that contains the characters of the specified subarray of the character array.
      Throws:
      IndexOutOfBoundsException - ifoffset is negative, orcount is negative, oroffset+count is larger thandata.length.

    • copyValueOf

      public static String copyValueOf(char[] data, int offset, int count)
      Parameters:
      data - the character array.
      offset - initial offset of the subarray.
      count - length of the subarray.
      Returns:
      aString that contains the characters of the specified subarray of the character array.
      Throws:
      IndexOutOfBoundsException - ifoffset is negative, orcount is negative, oroffset+count is larger thandata.length.

    • copyValueOf

      public static String copyValueOf(char[] data)
      Equivalent tovalueOf(char[]).
      Parameters:
      data - the character array.
      Returns:
      aString that contains the characters of the character array.

    • valueOf

      public static String valueOf(boolean b)
      Returns the string representation of theboolean argument.
      Parameters:
      b - aboolean.
      Returns:
      if the argument istrue, a string equal to"true" is returned; otherwise, a string equal to"false" is returned.

    • valueOf

      public static String valueOf(char c)
      Returns the string representation of thecharargument.
      Parameters:
      c - achar.
      Returns:
      a string of length1 containing as its single character the argumentc.

    • valueOf

      public static String valueOf(int i)
      Returns the string representation of theint argument.

      The representation is exactly the one returned by theInteger.toString method of one argument.

      Parameters:
      i - anint.
      Returns:
      a string representation of theint argument.
      See Also:

    • valueOf

      public static String valueOf(long l)
      Returns the string representation of thelong argument.

      The representation is exactly the one returned by theLong.toString method of one argument.

      Parameters:
      l - along.
      Returns:
      a string representation of thelong argument.
      See Also:

    • valueOf

      public static String valueOf(float f)
      Returns the string representation of thefloat argument.

      The representation is exactly the one returned by theFloat.toString method of one argument.

      Parameters:
      f - afloat.
      Returns:
      a string representation of thefloat argument.
      See Also:

    • valueOf

      public static String valueOf(double d)
      Returns the string representation of thedouble argument.

      The representation is exactly the one returned by theDouble.toString method of one argument.

      Parameters:
      d - adouble.
      Returns:
      a string representation of thedouble argument.
      See Also:

    • intern

      public String intern()
      Returns a canonical representation for the string object.

      A pool of strings, initially empty, is maintained privately by theclassString.

      When the intern method is invoked, if the pool already contains astring equal to thisString object as determined bytheequals(Object) method, then the string from the pool isreturned. Otherwise, thisString object is added to thepool and a reference to thisString object is returned.

      It follows that for any two stringss andt,s.intern() == t.intern() istrueif and only ifs.equals(t) istrue.

      All literal strings and string-valued constant expressions areinterned. String literals are defined in section3.10.5 of theThe Java Language Specification.

      Returns:
      a string that has the same contents as this string, but is guaranteed to be from a pool of unique strings.

    • repeat

      public String repeat(int count)
      Returns a string whose value is the concatenation of thisstring repeatedcount times.

      If this string is empty or count is zero then the emptystring is returned.

      Parameters:
      count - number of times to repeat
      Returns:
      A string composed of this string repeatedcount times or the empty string if this string is empty or count is zero
      Throws:
      IllegalArgumentException - if thecount is negative.
      Since:
      11

    • describeConstable

      public Optional<String> describeConstable()
      Returns anOptional containing the nominal descriptor for thisinstance, which is the instance itself.
      Specified by:
      describeConstable in interface Constable
      Returns:
      anOptional describing theString instance
      Since:
      12

    • resolveConstantDesc

      public String resolveConstantDesc(MethodHandles.Lookup lookup)
      Resolves this instance as aConstantDesc, the result of which isthe instance itself.
      Specified by:
      resolveConstantDesc in interface ConstantDesc
      Parameters:
      lookup - ignored
      Returns:
      theString instance
      Since:
      12