[概述](%E6%A6%8233%E8%BF%B0.md) [对象的哈希值](%E5%AF%B9%E8%B1%A1%E7%9A%84%E5%93%88%E5%B8%8C%E5%80%BC.md) [HashSet](HashSet.md) [LinkedHashSet](LinkedHashSet.md) [保证自定义元素的唯一性(重写)](%E4%BF%9D%E8%AF%81%E8%87%AA%E5%AE%9A%E4%B9%89%E5%85%83%E7%B4%A0%E7%9A%84%E5%94%AF%E4%B8%80%E6%80%A7%E9%87%8D%E5%86%99.md) [ArrayList和HashSet的contains原理](ArrayList%E5%92%8CHashSet%E7%9A%84contains%E5%8E%9F%E7%90%86.md)