检测 JVM 内存对象

检测 JVM 对象布局

jmap -histo 6 | head -n 20

root@l3:~# jmap -histo 6 | head -n 20

 num     #instances         #bytes  class name
----------------------------------------------
   1:         15023       38889232  [I
   2:        385429       27157144  [C
   3:         35831       18371584  [B
   4:         48181       10464312  [Ljava.lang.Object;
   5:        368722        8849328  java.lang.String
   6:        126032        3024768  java.lang.Long
   7:        124097        2978328  com.jansora.app.analysis.application.provider.beike.second.vo.TimelineCountVo
   8:         86868        2779776  java.util.concurrent.ConcurrentHashMap$Node
   9:         27304        2402752  java.lang.reflect.Method
  10:         18939        2090856  java.lang.Class
  11:         51209        1638688  java.util.HashMap$Node
  12:         10213        1124440  [Ljava.util.HashMap$Node;
  13:          2106        1067040  [Lcom.alibaba.nacos.shaded.io.grpc.netty.shaded.io.netty.util.Recycler$DefaultHandle;
  14:         21277        1021296  org.springframework.core.ResolvableType
  15:           547        1010832  [Ljava.util.concurrent.ConcurrentHashMap$Node;
  16:         22833         913320  java.util.LinkedHashMap$Entry
  17:         43925         702800  java.lang.Object