Question

I have some class files from a .jar file. I am looking for a class with a Main method, so I can see how this program works without its web baggage.

>javap HaploGrepServer/HaploGrepMain
Compiled from "HaploGrepMain.java"
public class HaploGrepServer.HaploGrepMain extends java.lang.Object{
    public HaploGrepServer.HaploGrepMain();
    public static void main(java.lang.String[])       throws java.io.IOException;
}

Great! I’ve found it

>java HaploGrepServer/HaploGrepMain
Exception in thread "main" java.lang.NoClassDefFoundError: org/restlet/Component
    at java.lang.ClassLoader....

OK I can add that

>java -cp org.restlet.jar HaploGrepServer/HaploGrepMain
Exception in thread "main" java.lang.NoClassDefFoundError: HaploGrepServer/HaploGrepMain
Caused by: java.lang.ClassNotFoundException: HaploGrepServer.HaploGrepMain
    at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: HaploGrepServer/HaploGrepMain. Program will exit.

what gives?

Answer 1

When you’re invoking a class within a package, try using dots to separate the package components, not slashes:

java -cp .:org.restlet.jar HaploGrepServer.HaploGrepMain