How to find the code related with memory usage for java hprof trace id 300000

[Steve Jiang]

Hi,

I tried to use hprof paramter to get the HPROF for memory usage checking. The command is like below.

javac -J-agentlib:hprof=heap=dump test.java

I got the hprof file. Based on trace ID, I can find most code which spend the memory from hprof file, but some of memory usage with trace id 300000, I can not find the valuable information for the memory usage from hprof file, It just marked as empty, and I don't know what exactly means for those memory usage , and which part is using that.

I atatched the sumary of hprof file and some trace id 3000000 below. Does someone know how we can find tracce 300000 memory usage?


TRACE 300000:
<empty>
.............

CLS 5001b4bd (name=javax.lang.model.element.VariableElement[], trace=300000)
super 50000119
CLS 5001b4be (name=javax.lang.model.element.Element[], trace=300000)
super 50000119

................

rank self accum bytes objs bytes objs trace name
1 46.98% 46.98% 11534304 240298 77470080 1613960 305622 java.nio.HeapCharBuffer
2 46.98% 93.97% 11534256 240297 77469984 1613958 305825 java.nio.HeapCharBuffer

4 0.81% 95.60% 200016 1 200016 1 303579 java.lang.Object[]
5 0.51% 96.10% 124640 1569 124640 1569 300000 char[]
6 0.38% 96.49% 94504 376 94504 376 301147 byte[]
7 0.15% 96.64% 37864 1556 37864 1556 300000 java.lang.String
8 0.12% 96.76% 28512 571 28512 571 300000 java.lang.Object[]
9 0.11% 96.87% 28152 589 28152 589 301144 char[]
10 0.10% 96.98% 25504 8 25504 8 300000 byte[]
11 0.10% 97.08% 24448 326 24448 326 306292 int[]

13 0.06% 97.23% 14136 589 14136 589 301143 java.lang.String
14 0.04% 97.28% 10432 326 10432 326 306294 sun.misc.FDBigInteger

16 0.04% 97.36% 10064 74 10064 74 305763 long[]
17 0.04% 97.40% 9584 112 9968 117 303246 char[]
18 0.04% 97.43% 8768 3 8768 3 303134 java.nio.ByteBuffer[]

20 0.03% 97.50% 8208 1 8208 1 305607 byte[]

23 0.02% 97.57% 4640 257 4640 257 300000 java.lang.Integer
24 0.02% 97.59% 4416 105 4968 117 303252 char[]


Thanks

[Steve Jiang]

Could someone help me for this issue?

Thanks

[Campbell Ritchie]

Don't know, I am afraid. I shall try duplicating your post elsewhere to try and get it more attention, but maybe nobody knows.