[String,StringBuffer,StringBuilder](../常用API/string.md) [正则,Date,DateFormat,Calendar](../正则,Date,DateFormat,Calendar.md) [包装类,System,Math,Arrays,BigInteger,BigDecimal](../包装类,System,Math,Arrays,BigInteger,BigDecimal.md) [集合,迭代器,增强for,泛型](../集合,迭代器,增强for,泛型.md) [List,set,判断集合唯一](../List,set,判断集合唯一.md) [map,Entry,HashMap,Collections](../map,Entry,HashMap,Collections.md)