Created attachment 135110 [details]
Test case with ant SE project

I can reproduce the dreaded "Uncompilable source code" error once again with a simple series of copy operations.

In this case, it manifests itself with a different error, java.lang.VerifyError.

How I do it:

- Create a Java SE project (see attached project)
- Map some java files from a directory outside the project in the favorites window
- Delete two files from the source root of the project: _netin.java, _netin.gif
- Copy two files: _netin.java, _netin.gif from favorites into the root package of the project, using multiple selection and [Ctrl+C]
- Copy the files again so that they produce the _1 file prefixes. The duplicate java file has an error as expected
- Delete the two _1 files that were copied again
- Run the project

Exception in thread "main" java.lang.VerifyError: Constructor must call super() or this() before return in method _netin.<init>()V at offset 0

I can fix the error:

- Delete _netin.java and copy it again

Notes:

The project cannot run properly because of more missing files, but the errors occur later so that should be ok.

To verify that this is in fact the "Uncompilable source code" error, I search the classes in the build directory for the string and find it only in _netin.class

This easily happens if I use multiple selection in the favorites window and forget to reset this multiple selection.

Then I have to delete the duplicate files which causes the error.