From 67e2c723aff4502501e0ac567ac5364348f6f3d7 Mon Sep 17 00:00:00 2001
From: Peter Tripp <peter@chartio.com>
Date: Tue, 16 Feb 2016 11:27:52 -0800
Subject: [PATCH] Java debug tools. Jstack, jmap and jhat.

---
 pages/common/jhat.md   | 11 +++++++++++
 pages/common/jmap.md   | 19 +++++++++++++++++++
 pages/common/jstack.md | 15 +++++++++++++++
 3 files changed, 45 insertions(+)
 create mode 100644 pages/common/jhat.md
 create mode 100644 pages/common/jmap.md
 create mode 100644 pages/common/jstack.md

diff --git a/pages/common/jhat.md b/pages/common/jhat.md
new file mode 100644
index 000000000..d5ff16815
--- /dev/null
+++ b/pages/common/jhat.md
@@ -0,0 +1,11 @@
+# jhat
+
+> Java Heap Analysis Tool.
+
+- Analyze a heap dump (from jmap), view via http on port 7000:
+
+`jhat {{dump_file.bin}}`
+
+- Analyze a heap dump, specifying an alternate port for the http server:
+
+`jhat -p {{port}} {{dump_file.bin}}`
diff --git a/pages/common/jmap.md b/pages/common/jmap.md
new file mode 100644
index 000000000..02e32aa3f
--- /dev/null
+++ b/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}}`
diff --git a/pages/common/jstack.md b/pages/common/jstack.md
new file mode 100644
index 000000000..80439ee08
--- /dev/null
+++ b/pages/common/jstack.md
@@ -0,0 +1,15 @@
+# jstack
+
+> Java Stack Trace Tool.
+
+- Print java stack traces for all threads in a java process:
+
+`jstack {{java_pid}}`
+
+- Print mixed mode (java/c++) stack traces for all threads in a java process:
+
+`jstack {{java_pid}}`
+
+- Print stack traces from java core dump:
+
+`jstack {{/usr/bin/java}} {{file.core}}`