Bug 10403 Project creation should confirm the bin directory can be scrubbed
When a user creates a new project for an existing directory structure, we should confirm that the output directory can be deleted then rebuilt. Some users are creating projects & pointing the output folder at a bin directory which contains more than just .class files which can be rebuilt from the available .java files.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/BuildPathsBlock.java
/**
	 * Creates a runnable that sets the configured build paths.
	 */
	public IRunnableWithProgress getRunnable() {
		final List classPathEntries= fClassPathList.getElements();
		final IPath path= getOutputLocation();
		
		return new IRunnableWithProgress() {
			public void run(IProgressMonitor monitor) throws InvocationTargetException {
				if (monitor == null) {
					monitor= new NullProgressMonitor();
				}				
				monitor.beginTask(NewWizardMessages.getString("BuildPathsBlock.operationdesc"), 10); 
				try {
					createJavaProject(classPathEntries, path, monitor);
				} catch (CoreException e) { 
					throw new InvocationTargetException(e);
				} finally {
					monitor.done();
				}
			}
		};
	}		
	
	/**
	 * Creates the Java project and sets the configured build path and output location.
	 * If the project already exists only build paths are updated.