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
result[0]= MessageDialog.openQuestion(shell, title, message);
			}
		});
		return result[0];
	}
	public static IVMInstall findMatchingJREInstall(String compliance) {
		IVMInstallType[] installTypes= JavaRuntime.getVMInstallTypes();
		for (int i= 0; i < installTypes.length; i++) {
			IVMInstall[] installs= installTypes[i].getVMInstalls();
			for (int k= 0; k < installs.length; k++) {
				if (hasMatchingCompliance(installs[k], compliance)) {
					return installs[k];
				}
			}
		}
		return null;
	}
	
	public static boolean hasMatchingCompliance(IVMInstall inst, String compliance) {
		if (!(inst instanceof IVMInstall2))
			return false;
		
		String version= JavaModelUtil.getCompilerCompliance((IVMInstall2) inst, null);
		if (version != null && version.startsWith(compliance)) {
			return true;
		}
		return false;
	}
}