Bug 13034 Cannot create a Source Folder in a new Java Project
build 20020404 If you try and create a Source Folder in a Java Project you have just created you get an error preventing you from hitting finish. STEPS 1) Create Java Project Foo 2) Open New->Source Folder 3) Enter Bar as the name - you will get "Cannot nest entry Bar inside entry Foo/Bar" 4) Create a folder Bar. 5) Add it as a source folder in the Properties Dialog for Foo. No problem.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/NewSourceFolderWizardPage.java
IRunnableWithProgress runnable= fBuildPathsBlock.getRunnable(fBuildPathsBlock.getRemoveOldBinariesQuery(getShell()));
				if (invokeRunnable(runnable)) {
					setReturnCode(OK);
				} else {
					setReturnCode(CANCEL);
				}
			}
			close();
		}
		
		private boolean invokeRunnable(IRunnableWithProgress runnable) {
			IRunnableWithProgress op= new WorkspaceModifyDelegatingOperation(runnable);
			try {
				getWizard().getContainer().run(false, true, op);
			} catch (InvocationTargetException e) {
				Shell shell= getShell();
				String title= NewWizardMessages.getString("NewSourceFolderWizardPage.op_error.title"); 
				String message= NewWizardMessages.getString("NewSourceFolderWizardPage.op_error.message");				 
				ExceptionHandler.handle(e, shell, title, message);
				return false;
			} catch  (InterruptedException e) {
				return false;
			}
			return true;
		}		
	}
	
	private boolean showClassPathPropertyPage() {
		EditClassPathDialog dialog= new EditClassPathDialog(getShell());
		dialog.setTitle(NewWizardMessages.getString("NewSourceFolderWizardPage.EditClassPathDialog.title"));