泛型类

WeakReference,ThreadLocal,ArrayList，HashMap,HashSet

public abstract class Reference<T> {
    private T referent;  
    public T get() {
        return this.referent;
    }

    Reference(T referent) {
        this(referent, null);
    }

    Reference(T referent, ReferenceQueue<? super T> queue) {
        this.referent = referent;
        this.queue = (queue == null) ? ReferenceQueue.NULL : queue;
    }
    ...
}


public class WeakReference<T> extends Reference<T> {


    public WeakReference(T referent) {
        super(referent);
    }

    public WeakReference(T referent, ReferenceQueue<? super T> q) {
        super(referent, q);
    }

}

泛型接口

List,Map,Set

public interface List<E> extends Collection<E> {
...
}

public interface Map<K,V> {
    int size();
    boolean isEmpty();
    ...
}

public interface Set<E> extends Collection<E> {
    boolean add(E e);
    ...
}

泛型方法

ArrayList的add方法：

    public boolean add(E e) {
        ensureCapacityInternal(size + 1);  // Increments modCount!!
        elementData[size++] = e;
        return true;
    }