JVM Explorer

JVM Explorer is a Java desktop application for browsing loaded class files inside locally running Java Virtual Machines.

Features

• Browse local JVMs
• View all classes inside each JVM
• Search to find specific classes (supports regex)
• View classloader hierarchy
• View decompiled bytecode
• View disassembled bytecode
• Export loaded classes to a JAR file
• Browse the state of all static variables in a class (and their nested fields)
• Modify the state of static variables (and their nested fields)
• Replace class file definitions
• View system properties of running JVMs
• Run JAR files with a patched ProcessBuilder to remove any -XX:+DisableAttachMechanism argument

Getting Started

There are two ways to run the application. Execute a provided JAR file or build and run it yourself. This application is intended to run on Java 11+ and can attach to JVMs running Java 7+.

Run JAR:

1. Download the jvm-explorer JAR file from the latest release
2. Run with at least Java 11

Build and run:

1. Clone with Git

git clone https://github.com/Naton1/jvm-explorer.git

2. Change into the project directory

cd jvm-explorer

3. Run with Gradle

./gradlew run

Troubleshooting

Two logs files application.log and agent.log are created at [User Home]/jvm-explorer/logs

• Must run the JAR with a Java version of at least Java 11
• Must attach to a JVM running a Java version of at least Java 7
• Must attach to a JVM running the same architecture - a 32-bit JVM must attach to a 32-bit JVM
• May have to attach to a JVM that was started by the same user
• Must attach to a JVM that supports the Java Attach API
• If you run an old version of this application and attach to a JVM, then update to a newer version and try to re-attach, the agent will be outdated. If there were changes to the client-server protocol, the agent will fail. Restart the target JVM to fix this.

Note: this uses the Java Attach API, so any limitations that come with that will apply here.

Project Principles

• Maintain a simple and easy-to-use interface
• Take advantage of attaching to running JVMs - this is not a traditional GUI decompiler

Possible Enhancements

• Plugins/scripting
• Multiple decompilers
• Inserting code (compile java code)
• Editing bytecode
• Execute code in attached JVM via JShell
• Tabs/open multiple classes
• Search code
• Detect changes between current classes and previous classes
• Internationalization

License

MIT License