JAVA Print Heap Dump

Question

I work with Java 1.7 and I want to print Heap Dump from java

...
Object heapDump=.... ;
...

System.out.println(heapDump);

Can anybody help me?

score 3 · Accepted Answer · edited Nov 25 '13 at 09:45

3

Use jmap:

jmap -dump:format=b,file=heap.bin <pid>

refer to Java 7 jmap tutorial.

edited Nov 25 '13 at 09:45

prime

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answered Nov 25 '13 at 09:39

harsh

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jmap -dump:format=b,file=/tmp/heap.bin 3894 throws exeption 3894: well-known file is not secure – javagc Nov 25 '13 at 10:00
2

You should try changing the file location to somewhere accessible, see similar issue and resolution: http://stackoverflow.com/questions/9100149/jstack-well-known-file-is-not-secure – harsh Nov 25 '13 at 10:02

score 0 · Answer 2 · answered Nov 25 '13 at 09:42

0

You can use the HotSpotDiagnosticMXBean for creating a heap dump programmatically.

answered Nov 25 '13 at 09:42

Kai Sternad

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thows error java.lang.UnsatisfiedLinkError: sun.management.Flag.initialize()V – javagc Nov 25 '13 at 10:00
@javagc What exactly did you do ? Which Hotspot version / vendor do you have ? – Kai Sternad Nov 25 '13 at 10:05

score 0 · Answer 3 · answered Nov 25 '13 at 09:57

You can't print the Heap Dump directly using S.O.P Statement. But you can dump all the data in a file. JVM will create heap dump every time when your application throws an OutOfMemoryError. HeapDumpPath is used to set location of heap dumps.

We can also use jmap from our code. Assume name,pid are the fileds retrieving. To get a pid from code use we need to use java.lang.management.ManagementFactory.

String name = ManagementFactory.getRuntimeMXBean().getName();
String pid = name.substring(0, name.indexOf("@"));
After that we can start jmap process like this:
String[] cmd = { "jmap", "-dump:file=D:\\temp\\heapdumps\\dump.bin", pid };
Process p = Runtime.getRuntime().exec(cmd);

JAVA Print Heap Dump

3 Answers3