红黑树的JAVA实现。红黑树仍然不是平衡树，但是统计性能要好于AVL树。要保持红黑树的规则，主要通过两类操作，一类是换色，一类还是旋转。-JAVA red-black tree implementation. Red-black tree is still not balanced tree, but the statistical performance is better than the AVL tree. Red-black tree to keep the rules, mainly