Is there a way to know if a Java program was started from the command line or from a jar file?

Question

I want to either display a message in the console or a pop up, so in case a parameter is not specified, I want to know to which should I display

Something like:

Answer 1

The System.console() trick seems to do the work.

Here's an alternative: there's a method in the class Class getProtectionDomain() which may be used to know the source of the code the the location from there.

The funny is, this method is available since 1.2

I knew I used this before, here's the original answer by erickson

Here's the proof of concept:

public class FromJar {
    public static void main( String [] args ) {
        if ( FromJar.class
                 .getProtectionDomain()
                 .getCodeSource()
                 .getLocation()
                 .getFile()
                 .endsWith(".jar") ) {

            javax.swing.JOptionPane.showMessageDialog( null, "Launched from Jar" );

       } else {
            System.out.println("Launched NOT from Jar :P ");
       }
    }
}

Here's a short ( 1m aprox ) video to see this code running ( and being written with cat :-o )