Question

When I run

char c= '\u0000'; 
System.out.println(c);

in Eclipse,it prints a little square which means a null character.
But it prints ‘a’ when I run it in CLI.
Then I run it on other computers, some print ‘a’, some print a space.

Why would this happen?

My OS is Windows 7 professional-32bit.The other systems are windows xp.
My java version is jdk_1.6.0update12.

Answer 1

It does not print a for me:

public class Mkt {
 public static void main(String[] args) {
    char c= '\u0000'; 
    System.out.println("-" + c + "-");
  }
}

$ javac Mkt.java && java Mkt
--

Ubuntu 11.10 here:

$ java -version
java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
Java HotSpot(TM) 64-Bit Server VM (build 20.1-b02, mixed mode)

Things to check / try:

• Change the font of your terminal window
• Did you try with other Java versions on your machine?
• Is there something different between your machine and others you tried?
• Try it from within Cygwin
• Try some different console emulator, e.g. Console
• Redirect to file (java Mkt > some_file.txt) and see what’s in it, preferably with some hex editor
• Make a small Swing application and display that in JTextArea to see if it displays the same
• What does \u0001 display?