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/preferences/ComplianceConfigurationBlock.java
private ArrayList fComplianceControls;
	private PixelConverter fPixelConverter;
	private String[] fRememberedUserCompliance;
	
	private static final int IDX_ASSERT_AS_IDENTIFIER= 0;
	private static final int IDX_ENUM_AS_IDENTIFIER= 1;
	private static final int IDX_SOURCE_COMPATIBILITY= 2;
	private static final int IDX_CODEGEN_TARGET_PLATFORM= 3;
	private static final int IDX_COMPLIANCE= 4;
	private static final int IDX_INLINE_JSR_BYTECODE= 5;
	private IStatus fComplianceStatus;
	private Link fJRE50InfoText;
	private Composite fControlsComposite;
	private ControlEnableState fBlockEnableState;
	public ComplianceConfigurationBlock(IStatusChangeListener context, IProject project, IWorkbenchPreferenceContainer container) {
		super(context, project, getKeys(), container);
		fBlockEnableState= null;
		fComplianceControls= new ArrayList();
			
		fComplianceStatus= new StatusInfo();
		
		fRememberedUserCompliance= new String[] { 
			getValue(PREF_PB_ASSERT_AS_IDENTIFIER),
			getValue(PREF_PB_ENUM_AS_IDENTIFIER),
			getValue(PREF_SOURCE_COMPATIBILITY),
			getValue(PREF_CODEGEN_TARGET_PLATFORM),
			getValue(PREF_COMPLIANCE),
			getValue(PREF_CODEGEN_INLINE_JSR_BYTECODE),
		};
	}