jmap

Print heap summary

$ jmap -heap [pid]

$ jmap -dump:format=b,file=[heap.hprof] [pid]

$ jmap -dump:live,format=b,file=[heap.hprof] [pid]

$ jmap -histo [pid]

$ jmap -histo:live [pid]

jmap [options] pid

jmap prints memory maps for Java processes. It generates heap dumps and object histograms.
The tool is essential for memory analysis and leak detection. Heap dumps can be analyzed with tools like MAT.
jmap creates Java heap dumps.

PID

Target Java process ID.

Print heap summary.

Print object histogram.

Dump heap to file.

Only live objects.

Binary format.

Output file.

Display help information.

Part of JDK. May pause application. Large heaps create large dumps.

jmap has been part of the JDK since Java 5, providing memory analysis capabilities for running Java processes.

jhat(1), jstack(1), jinfo(1), jcmd(1)