错误：Attempt to invoke interface method 'boolean java.util.List.add(java.lang.Object)' on a null
2017-11-30 16:12
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好吧，原因很无语，居然 是没有初始化造成的。
解决：
原因是你定义了 List<E> lists;
但并没有初始化，应该这样写：
List<E> lists = new ArrayList<>();
解决：
原因是你定义了 List<E> lists;
但并没有初始化，应该这样写：
List<E> lists = new ArrayList<>();
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