java jmap直方图中的这些对象是什么？
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时间：2020-10-30 21:59:32 来源:igfitidea点击:
What are these objects in the jmap histogram?
提问by Chris Steinbach
I'm using jmap to get a histogram of the heap. I'm not sure what the objects are that are referred to as "[C", "[S", "[I" and "[B". Anyone know?
我正在使用 jmap 来获取堆的直方图。我不确定被称为“[C”、“[S”、“[I”和“[B”的对象是什么。有人知道吗？
$ jmap -histo 3299
num #instances #bytes class name
----------------------------------------------
1: 9804 19070632 [Ljava.util.HashMap$Entry;
2: 38074 6216960 [Ljava.lang.Object;
3: 62256 4727832 [C
4: 19665 3124744 <constMethodKlass>
5: 19665 2365864 <methodKlass>
6: 57843 2313720 java.lang.String
7: 1662 2060528 <constantPoolKlass>
8: 21121 1842344 [S
9: 37772 1743888 <symbolKlass>
10: 2554 1655632 [I
11: 63710 1529040 java.lang.Integer
12: 1662 1264184 <instanceKlassKlass>
13: 1515 1196224 <constantPoolCacheKlass>
14: 24351 1168848 java.util.HashMap$Entry
15: 18706 1047536 java.net.SocketTimeoutException
16: 4301 784416 [B
...
23: 2588 242616 [[I
回答by Joachim Sauer
[Cis achar[][Sis ashort[][Iis aint[][Bis abyte[][[Iis aint[][]
[C是一个char[][S是一个short[][I是一个int[][B是一个byte[][[I是一个int[][]
The JavaDoc for Class.getName()has the details.
