While exporting to .jar I found something...

Question

So yesterday I was messing around trying to export to .jar... I was successful, but when I exported I accidentally exported to .java... And then I noticed that I can export to really any extension... like example.dat... So I did that... Now my question is how can I decompile the code that I exported to 'example.dat'?
Thanks a bunch

Answer 1

Jar archives traditionally use a ".jar" extension (and so you should use that extension when you export the file). But in a lot of situations the extensions does not really matter. You can use any legal filename when creating/listing/expanding the archive. You can also use an archive of any name as part of your classpath.
public class JarTest {
    public static void main(String args[]) {
        System.out.println("Hello from JarTest");
pbrockway@linuxdeskd6off:~/JDC/temp$ javac -cp . JarTest.java
pbrockway@linuxdeskd6off:~/JDC/temp$ jar cf rose.dat JarTest.class
pbrockway@linuxdeskd6off:~/JDC/temp$ java -cp rose.dat JarTest
Hello from JarTest
pbrockway@linuxdeskd6off:~/JDC/temp$ jar tf rose.dat
META-INF/
META-INF/MANIFEST.MF
JarTest.class
pbrockway@linuxdeskd6off:~/JDC/temp$ An IDE may impose its own rules, but the tools that come with the JDK - java, javac, jar - work according to their documentation.