TreeMap

package java.util;

import java.io.Serializable;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;
import java.util.function.Consumer;

public class TreeMap<K,V>
    extends AbstractMap<K,V>
    implements NavigableMap<K,V>, Cloneable, java.io.Serializable {
    
    private final Comparator<? super K> comparator;

    private transient Entry<K,V> root;
    
    private transient int size = 0;

    public TreeMap() {
        comparator = null;
    }    
    
    public TreeMap(Comparator<? super K> comparator) {
        this.comparator = comparator;
    }
    
    static final class Entry<K,V> implements Map.Entry<K,V> {
        K key;
        V value;
        Entry<K,V> left;
        Entry<K,V> right;
        Entry<K,V> parent;
        boolean color = BLACK; // 红黑树
    }    
}