Bug 123786 Following bug 109980, the compliance 6.0 should be added to the compiler's compliance list.
If the JRE/JDK used is a 1.6/6.0 VM, then the compliance 6.0 should be available. Compliance 1.6 implies source level 1.6 and target level 1.6.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/BuildPathSupport.java
IJavaProject curr= jprojects[i];
				if (!curr.equals(currProject)) {
					IClasspathEntry[] entries= curr.getRawClasspath();
					for (int k= 0; k < entries.length; k++) {
						IClasspathEntry entry= entries[k];
						if (entry.getEntryKind() == elem.getEntryKind()
							&& entry.getPath().equals(elem.getPath())) {
							IPath attachPath= entry.getSourceAttachmentPath();
							if (attachPath != null && !attachPath.isEmpty()) {
								return attachPath;
							}
						}
					}
				}
			}
		} catch (JavaModelException e) {
			JavaPlugin.log(e.getStatus());
		}
		return null;
	}
	
	/**
	 * Finds a javadoc location for a new archive in the existing classpaths.
	 * @param elem The new classpath entry
	 * @return A javadoc location found in a similar classpath entry or <code>null</code>.
	 */
	public static String guessJavadocLocation(CPListElement elem) {
		if (elem.getEntryKind() == IClasspathEntry.CPE_CONTAINER) {
			return null;
		}