Question

I am trying to write Java console application, the code is quite simple:

public class ConsoleTest {
    public static void main(String[] args) {
        System.out.println("test");
    }
}

If I run this application from Eclipse, then i see “test” in Eclipse’s “Console”, but if I export my app as a “Runnable JAR file” and run it from Windows XP cmd.exe, then nothing is echoed to the console.

On the safe side, i tried to check System.console(), it returns null.

What can be wrong?

Answer 1

How are you running your program outside eclipse?

You should use command line like

java -jar yourjar.jar

or

java -cp yourjar.jar ConsoleTest

If you are occasionally using javaw instead no console output will be produced. The STDOUT of javaw is null. Probably this is what happens when you are clicking on your jar file.