memory map : print details of a specified process
References
man jmap- Understand the JVM - 2nd Edition - ZH Ver. - P144
- Java SE 14 Docs - Tools References -
jmap: https://docs.oracle.com/en/java/javase/14/docs/specs/man/jmap.html
# Dump all objects
jmap -dump:all,format=b,file=jmap-dump-all-12345.bin 12345
# Dump live objects
jmap -dump:live,format=b,file=jmap-dump-live-12345.bin 12345
# Show class loader statistics
jmap -clstats 12345jmap [ option ] pid
jmap [ option ] executable core
jmap [ option ] [ server-id@ ] remote-hostname-or-IP-clstats pidConnects to a running process and prints class loader statistics of Java heap.-finalizerinfo pidConnects to a running process and prints information on objects awaiting finalization.-histo[:live] pidConnects to a running process and prints a histogram of the Java object heap.- If the live suboption is specified, it then counts only live objects.
-dump:dump_options pidConnects to a running process and dumps the Java heap.- The dump_options include:
liveWhen specified, dumps only the live objects; if not specified, then dumps all objects in the heap.format=bDumps the Java heap in hprof binary formatfile=filenameDumps the heap to filename
- Example: jmap -dump:live,format=b,file=heap.bin pid
- The dump_options include:
# IntelliJ IDEA
$ jmap -clstats 581
Index Super InstBytes KlassBytes annotations CpAll MethodCount Bytecodes MethodAll ROAll RWAll Total ClassName
1 -1 82915176 504 0 0 0 0 0 24 616 640 [B
2 -1 24106760 504 0 0 0 0 0 24 616 640 [I
3 41 16969320 616 128 14272 109 4576 77952 18640 75632 94272 java.lang.String
4 -1 12357432 504 0 0 0 0 0 24 616 640 [Ljava.lang.Object;
5 41 7711064 672 0 22120 139 5679 95384 24632 95456 120088 java.lang.Class
6 41 5642144 584 0 1392 7 149 2656 1152 3800 4952 java.util.HashMap$Node
7 -1 4338136 504 0 0 0 0 0 32 616 648 [Ljava.util.HashMap$Node;
8 41 3878624 592 0 1368 9 213 2776 1488 3584 5072 java.util.concurrent.ConcurrentHashMap$Node
9 -1 2774168 504 0 0 0 0 0 24 616 640 [C
10 59539 2287296 1440 0 7008 64 2681 48848 11232 47056 58288 java.util.ArrayList
11 6 2131000 584 0 512 1 10 624 304 1648 1952 java.util.LinkedHashMap$Entry
12 41 1921024 528 0 888 2 45 808 432 2032 2464 com.intellij.util.containers.IntObjectLinkedMap$MapEntry
13 62782 1612680 792 0 7024 39 1023 13032 5984 15672 21656 org.jdom.Attribute
14 59539 1489584 1320 0 4672 29 2038 25488 6024 25960 31984 com.intellij.util.SmartList
15 -1 1365880 504 0 0 0 0 0 32 616 648 [Ljava.util.concurrent.ConcurrentHashMap$Node;
16 27 1335680 584 0 728 4 41 2504 552 3464 4016 com.intellij.reference.SoftReference
17 -1 1157888 504 0 0 0 0 0 24 616 640 [J
……
248324816 48508944 1177480 130153960 548287 26679441 185243808 100811760 283283120 384094880 Total
64.7% 12.6% 0.3% 33.9% - 6.9% 48.2% 26.2% 73.8% 100.0%
Index Super InstBytes KlassBytes annotations CpAll MethodCount Bytecodes MethodAll ROAll RWAll Total ClassName
…… ( max index : 65833 )# IntelliJ IDEA
$ jmap -finalizerinfo 581
No instances waiting for finalization foundPrints a histogram of the Java object heap
# IntelliJ IDEA
$ jmap -histo 581
num #instances #bytes class name (module)
-------------------------------------------------------
1: 793630 87757672 [B ([email protected])
2: 82437 28394672 [I ([email protected])
3: 722035 17328840 java.lang.String ([email protected])
4: 158293 12708400 [Ljava.lang.Object; ([email protected])
5: 65850 7711960 java.lang.Class ([email protected])
6: 206109 6595488 java.util.HashMap$Node ([email protected])
7: 168315 5386080 java.util.concurrent.ConcurrentHashMap$Node ([email protected])
8: 113575 4543000 java.security.AccessControlContext ([email protected])
9: 29264 4471784 [Ljava.util.HashMap$Node; ([email protected])
10: 10548 3202744 [C ([email protected])
11: 116227 2789448 java.util.ArrayList ([email protected])
12: 47094 2637264 java.util.concurrent.ConcurrentHashMap$KeyIterator ([email protected])
13: 11443 2380144 sun.java2d.SunGraphics2D ([email protected])
14: 70641 2260512 com.intellij.util.containers.LockFreeCopyOnWriteArrayList$COWIterator
15: 53275 2131000 java.util.LinkedHashMap$Entry ([email protected])
16: 65253 2088096 java.util.concurrent.locks.AbstractQueuedSynchronizer$Node ([email protected])
17: 60032 1921024 com.intellij.util.containers.IntObjectLinkedMap$MapEntry
18: 26369 1898568 java.awt.geom.AffineTransform ([email protected])
19: 40317 1612680 org.jdom.Attribute
……
Total 5532528 296656320
…… ( max num : 32093 )Prints a histogram of only the live Java object heap
# IntelliJ IDEA
$ jmap -histo:live 581
num #instances #bytes class name (module)
-------------------------------------------------------
1: 740083 82895920 [B ([email protected])
2: 81941 24101240 [I ([email protected])
3: 707072 16969728 java.lang.String ([email protected])
4: 142229 12356432 [Ljava.lang.Object; ([email protected])
5: 65850 7711960 java.lang.Class ([email protected])
6: 176314 5642048 java.util.HashMap$Node ([email protected])
7: 29166 4338056 [Ljava.util.HashMap$Node; ([email protected])
8: 121197 3878304 java.util.concurrent.ConcurrentHashMap$Node ([email protected])
9: 5506 2774256 [C ([email protected])
10: 95301 2287224 java.util.ArrayList ([email protected])
11: 53275 2131000 java.util.LinkedHashMap$Entry ([email protected])
12: 60032 1921024 com.intellij.util.containers.IntObjectLinkedMap$MapEntry
13: 40317 1612680 org.jdom.Attribute
14: 62066 1489584 com.intellij.util.SmartList
15: 2030 1365880 [Ljava.util.concurrent.ConcurrentHashMap$Node; ([email protected])
16: 33392 1335680 com.intellij.reference.SoftReference
17: 9172 1151936 [J ([email protected])
……
Total 4377356 24829144
…… ( max num : 31953 )Dump all objects
# IntelliJ IDEA
$ jmap -dump:all,format=b,file=jmap-dump-all-581.bin 581
Heap dump file createdDump only live objects
# IntelliJ IDEA
$ jmap -dump:live,format=b,file=jmap-dump-all-581.bin 581
Heap dump file created