HashMap 1.8的源码分析一

public class HashMap<K,V> extends AbstractMap<K,V>
    implements Map<K,V>, Cloneable, Serializable {

    private static final long serialVersionUID = 362498820763181265L;

 static final int DEFAULT_INITIAL_CAPACITY = 1 << 4; // aka 16

 static final int MAXIMUM_CAPACITY = 1 << 30;

  static final float DEFAULT_LOAD_FACTOR = 0.75f;

static final int TREEIFY_THRESHOLD = 8;

static final int UNTREEIFY_THRESHOLD = 6;

/**
 * The smallest table capacity for which bins may be treeified.
 * (Otherwise the table is resized if too many nodes in a bin.)
 * Should be at least 4 * TREEIFY_THRESHOLD to avoid conflicts
 * between resizing and treeification thresholds.
 */
static final int MIN_TREEIFY_CAPACITY = 64;

 static final int hash(Object key) {
        int h;
        return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16);
    }