How to have an object/class tell me what jar file it is from

Question

In Eclipse and a class is being loaded that should not be possible. In debug mode, I can pause it and see a call to class a.b.c BUT a.b.c class should exist anywhere since it has been renamed. My assumption is that there is an old jar file being called...but I cannot find it. So how do I find the jar file that class a.b.c is in while in debug mode in eclipse ? Either through an eclipse menu option or via Java and using reflection to get the object to tell me its own jar file.

Thanks.

Answer 1

You can use the class loader to retrieve the URL of a resource. This works also for classes. To get the location of the java.lang.String class:

X.class.getClassLoader().getResource("java/lang/String.class");

Output:

jar:file:/C:/Program%20Files/Java/jdk1.6.0_17/jre/lib/rt.jar!/java/lang/String.class

Answer 2

If you fire up your JVM using -verbose:class (you can set this as a JVM option in Eclipse) you can see exactly which classes are being loaded when, and I think from where.