2503. Java - Thread Dumps & Analysis
Thread Dumps

Thread Dumps, performance analysis.

1. Thread Dumps

A thread dump is a snapshot of the state of all threads that are part of the process. The state of each thread is presented with a so called stack trace, which shows the contents of a thread’s stack.

2. Capturing Thread Dumps

jps is useful tools for viewing information about running java processes.

$ jps -l
13856 johnny.algorithm.advanced.CyclicBarrierTest
13218 johnny.algorithm.advanced.CyclicBarrierTest
12467
99753
14600 sun.tools.jps.Jps

jstack is an effective command line tool to capture thread dumps.

jstack -l  13218

Java VisualVM is a graphical user interface tool that provides detailed information about the applications while they are running on a specified Java Virtual Machine (JVM).

jvisualvm

Java Mission Control (JMC) is a tool that collects and analyze data from Java applications running locally or deployed in production environments.

jmc

3. Analyze Thread Dumps

3.1 Thread Information from the Thread Dump File

  • Thread name: When using Java.lang.Thread class to generate a thread, the thread will be named Thread-(Number), whereas when using java.util.concurrent.ThreadFactory class, it will be named pool-(number)-thread-(number).
  • Priority: Represents the priority of the threads.
  • Thread ID: Represents the unique ID for the threads. (Some useful information, including the CPU usage or memory usage of the thread, can be obtained by using thread ID.)
  • Thread status: Represents the status of the threads.
  • Thread callstack: Represents the call stack information of the threads.
"pool-1-thread-13" prio=6 tid=0x000000000729a000 nid=0x2fb4 runnable [0x0000000007f0f000] java.lang.Thread.State: RUNNABLE

3.2 Deadlock

3.3 Performance

4. References