Exporting Java project as .jar file will complain that certain .java files aren't found

Question

When trying to export a project as a .jar file, Eclipse will complain that some files can't be found on the classpath:

Class files on classpath not found or not accessible for: 'proj/src/main/java/analysis/specification/VerifyVariableIsDefinedInsideTargetTerm.java'

Now, the interesting part is that these files haven't actually existed on the disk for ages. I guess I force Eclipse to refresh its database some way. I've tried doing F5 for a full build, but it seems to no avail. I've also tried the procedure described in this blog post, but the issue remains.

Answer 1

Error… I actually tripped on the reason for the problem a few moments ago…

All the files that were raising problems did actually exist on the project but were commented out (and thus, I didn't see them in the package explorer which is the view I generally use).

After deleting them, everything went fine. I still don't understand why would they raise errors in the JAR creation process, though…

EDIT: Here's an example of a commented out class:

package a.b.c

//import java.io.Closeable;

//public class Example implements Closeable {
//    public void close() throws IOException {
//        System.out.println("closed");
//    }
//}

Because the whole class is commented out, no Example.class is created. Whereas if the class is commented out like this:

package a.b.c

//import java.io.Closeable;

public class Example
//    implements Closeable
{
//    public void close() throws IOException {
//        System.out.println("closed");
//    }
}

an Example.class is created, although empty.

This may be a bug in eclipse. If you export the ant build script from eclipse and use that, it creates the JAR just fine.

Answer 2

This issue occurred to me also. However, the problem that I had was that I had JRE configuration issues in Eclipse.