Movatterモバイル変換

public classNullPointerExceptionextendsRuntimeException

Thrown when an application attempts to usenull in a case where an object is required. These include:

• Calling the instance method of anull object.
• Accessing or modifying the field of anull object.
• Taking the length ofnull as if it were an array.
• Accessing or modifying the slots ofnull as if it were an array.
• Throwingnull as if it were aThrowable value.

Applications should throw instances of this class to indicate other illegal uses of thenull object.NullPointerException objects may be constructed by the virtual machine as ifsuppression were disabled and/or the stack trace was not writable.