Pure speculation is that you're using a terminal that attempts to doword-wrapping rather than character-wrapping, and treatsB as a word character but# as a non-word character. So when it reaches the end of a line and searches for a place to break the line, it sees a# almost immediately and happily breaks there; whereas with theB, it has to keep searching for longer, and may have more text to wrap (which may be expensive on some terminals, e.g., outputting backspaces, then outputting spaces to overwrite the letters being wrapped).

But that's pure speculation.

I performed tests on Eclipse vs Netbeans 8.0.2, both with Java version 1.8;I usedSystem.nanoTime() for measurements.

Eclipse:

I got thesame time on both cases - around1.564 seconds.

Netbeans:

• Using "#":1.536 seconds
• Using "B":44.164 seconds

So, it looks like Netbeans has a bad performance on print to console.

After more research, I realized that the problem isline-wrapping of the max buffer of Netbeans (it's not restricted toSystem.out.println command), demonstrated by this code:

    for (int i = 0; i < 1000; i++) {        long t1 = System.nanoTime();        System.out.print("BBB......BBB"); // <- contains 1000 "B"s        long t2 = System.nanoTime();        System.out.println(t2 - t1);        System.out.println("");    }

The time results are less than 1 millisecond every iteration exceptevery fifth iteration, when the time result is around 225 milliseconds. Something like (in nanoseconds):

BBB...31744BBB...31744BBB...31744BBB...31744BBB...226365807BBB...31744BBB...31744BBB...31744BBB...31744BBB...226365807...

And so on.

Summary:

1. Eclipse works perfectly with "B"
2. Netbeans has a line-wrapping problem that can be solved (because the problem does not occur in eclipse)(without adding space after B ("B ")).

Yes, the culprit is definitely word-wrapping. When I tested your two programs, NetBeans IDE 8.2 gave me the following result.

1. First Matrix: O and # =6.03 seconds
2. Second Matrix: O and B =50.97 seconds

Looking at your code closely: you have used a line break at the end of the first loop. But you didn't use any line breaks in the second loop. So you are going to print a word with 1000 characters in the second loop. That causes a word-wrapping problem. If we use a non-word character " " after B, it takes only5.35 seconds to compile the program. And If we use a line break in the second loop after passing 100 values or 50 values, it takes only8.56 seconds and7.05 seconds respectively.

Random r = new Random();for (int i = 0; i < 1000; i++) {    for (int j = 0; j < 1000; j++) {        if (r.nextInt(4) == 0) {            System.out.print("O");        } else {            System.out.print("B");        }        if (j % 100 == 0) { // Adding a line break in second loop                  System.out.println();        }                        }    System.out.println("");                }

Another advice is to change the settings of NetBeans IDE. First of all, go to NetBeansTools and clickOptions. After that, clickEditor and go to theFormatting tab. Then selectAnywhere inLine Wrap Option. It will take almost 6.24% less time to compile the program.

• java
• performance
• loops
• for-loop
• system.out