为何一个 SpringBoot 堆内存中有大量的 Integer 对象？

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jmap -histo 19183 | head -20

 num     #instances         #bytes  class name
----------------------------------------------
   1:        223718      460271832  [I
   2:       2125963      273642920  [C
   3:        323214      142451944  [B
   4:       1498297       35959128  java.lang.String
   5:        535649       28576352  [Ljava.lang.Object;
   6:        472738       26473328  java.util.LinkedHashMap
   7:        632837       20250784  juc.locks.AbstractQueuedSynchronizer$Node
   8:        231974       17470032  [Ljava.util.HashMap$Node;
   9:        426575       17063000  java.util.LinkedHashMap$Entry
  10:        452507       14480224  java.util.LinkedHashMap$LinkedKeyIterator
  11:        481794       11563056  java.util.ArrayList
  12:        108053        9508664  java.lang.reflect.Method
  13:          5536        9187024  [Ljava.util.concurrent.ConcurrentHashMap$Node;
  14:        267553        8561696  java.util.ArrayList$Itr
  15:        291985        7850920  [Ljava.lang.String;
  16:        125609        6029232  java.util.HashMap
  17:        165873        5307936  java.util.concurrent.ConcurrentHashMap$Node

一般来说，String 对象更多一点，也就是 [C 更多才对。。。好奇怪

3 replies • 2020-05-24 11:57:43 +08:00