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
* Sets the 'missing' state of the entry.
	 */
	public void setIsMissing(boolean isMissing) {
		fIsMissing= isMissing;
	}
	/**
	 * Returns if a entry is exported (only applies to libraries)
	 * @return Returns a boolean
	 */
	public boolean isExported() {
		return fIsExported;
	}
	/**
	 * Sets the export state of the entry.
	 */
	public void setExported(boolean isExported) {
		if (isExported != fIsExported) {
			fIsExported = isExported;
			
			attributeChanged(null);
		}
	}
	/**
	 * Gets the project.
	 * @return Returns a IJavaProject
	 */
	public IJavaProject getJavaProject() {
		return fProject;
	}