Java debug tools. Jstack, jmap and jhat.

pages/common/jmap.md

@@ -0,0 +1,19 @@
+# jmap
+
+> Java Memory Map Tool.
+
+- Print shared object mappings for a java process (output like pmap):
+
+`jmap {{java_pid}}`
+
+- Print heap summary information:
+
+`java -heap {{filename.jar}} {{java_pid}}`
+
+- Print histogram of heap usage by type:
+
+`jmap -histo {{java_pid}}`
+
+- Dump contents of the heap into a binary file for analysis with jhat:
+
+`jmap -dump:format=b,file={{filename}} {{java_pid}}`