Java: jmap heap dump

To capture a heap dump using jmap we need to use the dump option:

jmap -dump:[live],format=b,file=<file-path> <pid>

Along with that option, we should specify several parameters:

• live: if set it only prints objects which have active references and discards the ones that are ready to be garbage collected. This parameter is optional
• format=b: specifies that the dump file will be in binary format. If not set the result is the same
• file: the file where the dump will be written to
• pid: id of the Java process

An example would be like this:

jmap -dump:live,format=b,file=/tmp/dump.hprof 12587

see also

• https://www.baeldung.com/java-heap-dump-capture
• 7 Ways to Capture Java Heap Dumps