Bug 28510 java build path inconsistency [build path]
20021216 select rt.jar in the package explorer open properties it allows you to set the javadoc location but for source attachment you are sent somewhere else it's inconsistent - on the java build path they both look sort of the same (they sit under the same node in the tree)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/CPListElement.java
return JavaCore.newProjectEntry(fPath, isExported());
			case IClasspathEntry.CPE_CONTAINER:
				return JavaCore.newContainerEntry(fPath, isExported());
			case IClasspathEntry.CPE_VARIABLE:
				IPath varAttach= (IPath) getAttribute(SOURCEATTACHMENT);
				return JavaCore.newVariableEntry(fPath, varAttach, null, isExported());
			default:
				return null;
		}
	}
	
	/**
	 * Gets the classpath entry path.
	 * @see IClasspathEntry#getPath()
	 */
	public IPath getPath() {
		return fPath;
	}
	/**
	 * Gets the classpath entry kind.
	 * @see IClasspathEntry#getEntryKind()
	 */	
	public int getEntryKind() {
		return fEntryKind;
	}
	/**
	 * Entries without resource are either non existing or a variable entry
	 * External jars do not have a resource
	 */
	public IResource getResource() {