The -l option is especially useful for deadlock detection and analyzing thread waiting states. It shows both standard monitor locks and locks from the java.util.concurrent package.

sudo apt install default-jdk

: jstack is part of the "devel" (development) package. For the latest version: sudo apt install default-jdk .

# Update the package list sudo apt update

Because jstack is an integral part of the , it is not available in the lightweight Java Runtime Environment (JRE) or the standard Ubuntu base packages. This article will guide you step-by-step on how to install the full JDK on Ubuntu to get jstack . Prerequisites

The most straightforward and highly recommended way to get jstack on Ubuntu is by installing the default JDK via the Advanced Package Tool ( apt ). The default JDK in Ubuntu is a symbolic link that points to the latest stable OpenJDK release.

jcmd -l

If you have multiple versions of Java installed, or if jstack is still not recognized, you need to configure your environment variables. 1. Set the default Java version

You can check if Java is installed on your Ubuntu system by running the following command in your terminal: * java -version. DigitalOcean Install the Java Runtime Environment - Ubuntu

JStack comes bundled with the JDK, so you need to have JDK installed on your Ubuntu system. If you haven't installed JDK yet, follow these steps:

export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64 export PATH=$PATH:$JAVA_HOME/bin

export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64 export PATH=$PATH:$JAVA_HOME/bin Use code with caution.

If your application requires a specific Java version (such as Java 11, 17, or 21), you can install it directly: sudo apt install openjdk-21-jdk -y For Java 17: sudo apt install openjdk-17-jdk -y For Java 11: sudo apt install openjdk-11-jdk -y Step 4: Verify the jstack Installation

jstack -l <PID> > detailed_thread_dump.txt

To install on Ubuntu, you must install the Java Development Kit (JDK)

How to Install jstack on Ubuntu: A Complete Guide The jstack command-line utility is an essential tool for Java developers and system administrators. It prints Java thread stack traces for a given Java process, helping you diagnose performance bottlenecks, deadlocks, and high CPU usage.

If you see output like /usr/bin/jstack , it’s already installed. If you see command not found , proceed with the installation.

Which (11, 17, 21, etc.) does your application use? Are you running Java inside a Docker container on Ubuntu?