Bug 45062 Don't filter output folder and class files
Create a Java project with source folder src and output folder bin. The bin folder will not be shown in the Packages Explorer. Create a Java project with source folder src and output folder output/bin. The output and bin folders are shown in the Packages Explorer. Implictly filtering out bin is confusing and inconsistent. A better way to do this would be to use a name filter for bin or add "Output folder" to the list of available filters.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
if (element != null && element.exists())
				return element;
			return input;
		}
		
		
		
		return JavaCore.create(JavaPlugin.getWorkspace().getRoot());	
	}
	
	/**
	 * Answer the property defined by key.
	 */
	public Object getAdapter(Class key) {
		if (key.equals(ISelectionProvider.class))
			return fViewer;
		if (key == IShowInSource.class) {
			return getShowInSource();
		}
		if (key == IShowInTargetList.class) {
			return new IShowInTargetList() {
				public String[] getShowInTargetIds() {
					return new String[] { IPageLayout.ID_RES_NAV };
				}
			};
		}
		return super.getAdapter(key);
	}
	/**
	 * Returns the tool tip text for the given element.