Observability of the Java Virtual Machine

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The JVM is one of the most observable runtimes. It provides us lots of tools for troubleshooting a JVM application in production. 1. Thread observability Threads are how the JVM actually does work. When something is wrong in production, the symptom is almost always a thread: stopped, blocked, leaking etc. Thread dumps work on any JVM with no  instrumentation, no agents, no restarts. <Example project link with /threaddump endpoint>         // (1) Deadlock — two threads grab the same pair of locks in opposite order.         new Thread(() -> grab(LOCK_A, LOCK_B), "deadlock-A-then-B").start();         new Thread(() -> grab(LOCK_B, LOCK_A), "deadlock-B-then-A").start(); http://localhost:8080/actuator/threaddump To list the JVMS, we can use the command below. PS C:\observe-jvm> jps -lv 25296 jdk.jcmd/sun.tools.jps.Jps -Dapplication.home=C:\Program Files\Microsoft\jdk-21.0.3.9-hotspot -Xms8m -Djdk.module.main=...
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DEVOPS

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This table shows imporant aspects of DEVOPS and related software products. The ones that I have used in the past are painted in red. I think this is a very nice table to look at alternative solutions to use for new projects. Of course some of them are essential:

  • Version control. (Subversion,  Git, ..)
  • Build tool. (Maven, Gradle, ..)
  • Testing. Unit Test, Stress Test, UI TEst. (JUnit, JMeter, Selenium)
  • Continuous Integration. (Bamboo, Continuum, ..)

 The others seem to depend on the size of the organization and the project. Some use AWS, others manage their own servers. 

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