垃圾回收
https://www.cnblogs.com/zuoxiaolong/p/life51.html
https://blog.csdn.net/qq_34560242/article/details/81020452
面经
https://www.nowcoder.com/discuss/experience?tagId=639
如何晋级
https://www.zhihu.com/question/39430220/answer/147663051
什么时候会 GC
https://blog.csdn.net/cy609329119/article/details/51771953
https://blog.csdn.net/pdf0824/article/details/77018879
