Arthas Java Diagnostic Tool: Installation, Common Commands, and Usage Guide

Arthas is an Alibaba‑open‑source Java diagnostic tool that enables dynamic tracing of Java code and real‑time JVM monitoring without stopping the application, supporting JDK 6+ on Linux, macOS, and Windows.

Installation

Download the boot jar and start it with wget https://alibaba.github.io/arthas/arthas-boot.jar followed by java -jar arthas-boot.jar . After starting, select the target application by its number.

Common Commands

1. stack – shows the call stack of a method, e.g., stack com.baomidou.mybatisplus.extension.service.IService getOne .

2. jad – decompiles a loaded class, e.g., jad cn.test.mobile.controller.order.OrderController or jad cn.test.mobile.controller.order.OrderController getOrderInfo .

3. sc (Search‑Class) – searches loaded classes by pattern, e.g., sc *OrderController* or sc -d cn.test.mobile.controller.order.OrderController .

4. watch – monitors method parameters and return values, e.g., watch cn.test.mobile.controller.order.OrderController getOrderInfo "{params,returnObj}" -x 2 .

5. trace – prints the internal call chain with timing, e.g., trace -j cn.test.mobile.controller.order.OrderController getOrderInfo and can filter by cost.

6. jobs – runs commands in background, e.g., trace -j cn.test.mobile.controller.order.OrderController getOrderInfo > test.out & , then list with jobs , manage with options job-timeout 2d and kill 76 .

7. logger – view and update logger levels, e.g., logger --name ROOT --level debug .

8. dashboard – displays real‑time JVM metrics such as thread states, CPU usage, memory usage, and GC statistics.

9. redefine – hot‑updates already loaded classes without restarting; workflow includes decompiling with jad --source-only , editing the source, compiling with mc -c 18b4aac2 OrderController.java -d ./ , and applying with redefine -c 18b4aac2 OrderController.class .

The article also covers troubleshooting when launching Arthas‑boot, such as selecting the correct Java process and changing telnet ports.