java.lang.ref
Classes 
PhantomReference sample code for java.lang.ref.PhantomReference definition code for java.lang.ref.PhantomReference
Reference sample code for java.lang.ref.Reference definition code for java.lang.ref.Reference
ReferenceQueue sample code for java.lang.ref.ReferenceQueue definition code for java.lang.ref.ReferenceQueue
SoftReference sample code for java.lang.ref.SoftReference definition code for java.lang.ref.SoftReference
WeakReference sample code for java.lang.ref.WeakReference definition code for java.lang.ref.WeakReference