View and analyze Java compiled bytecode directly inside VS Code
Features
1. Activity Bar Bytecode Explorer
Dedicated activity bar icon with a clean, hierarchical tree view of all compiled .class files.
Intelligent Package Compacting: Automatically collapses single-child packages (com.example.service instead of 3 deep folders).
Inner & Anonymous Classes Nesting: Nested classes (Outer$Inner.class, Outer$1.class) are neatly organized under their outer class with child badges.
Multi-Module Support: Seamlessly discovers build directories across multi-module Maven (target/classes), Gradle (build/classes), and Eclipse/VS Code (bin).
Instant Hot-Reload: A built-in file watcher detects re-compilations (mvn compile, ./gradlew build) and updates both the tree and any open bytecode viewer in real time.
Open any .java source file and click the "Java: Show Bytecode" button in the editor title bar to open its bytecode side-by-side (Split View).
Live Cursor Tracking: As you navigate or click lines in your .java file, the bytecode editor automatically scrolls and selects the exact corresponding JVM bytecode instruction!
3. One-Click Toolbar Toggles
No need to dig into configuration files to switch views. Three interactive toggles sit directly in the bytecode editor title bar:
Toggle Verbose (Constant Pool) ($(list-tree)) : Instantly hide or show the constant pool table and stack map frames to focus purely on method instructions.
Toggle Private Members ($(eye)) : Toggle visibility of private methods and fields (-p).
Toggle Line Number Tables ($(list-ordered)) : Toggle LineNumberTable and LocalVariableTable debug blocks (-l).
4. Document Outline & Breadcrumbs Navigation
Full integration with VS Code's Outline panel and Breadcrumbs.
Instantly jump between:
The Constant Pool table
Constructors (<init>)
Methods (main, getters, business logic)
Fields and constants
5. Interactive Constant Pool Hyperlinks
Every #index reference in the bytecode or constant pool (e.g. invokevirtual [#15](https://github.com/Houssam-OUATMANI/java-bytecode-viewer/issues/15) // Method ...) is rendered as an interactive hyperlink.
Ctrl + Click (or click) on #15 to jump straight to its declaration line in the Constant Pool!
6. Zero-Config & Lightning Fast
Auto-detects JDK: Scans JAVA_HOME, PATH, and standard installation paths on Windows, macOS, and Linux (JDK 8 up to Java 25+).
Smart Memory Cache: Avoids re-invoking JVM processes on tab switches by caching disassemblies with file modification timestamps (mtime).
Configuration
Customize the extension behavior via your VS Code Settings (Ctrl+, / Cmd+, and search for Java Bytecode):
Setting
Default
Description
javaBytecode.javapPath
""
Custom path to the javap executable. If empty, auto-detection is used.
javaBytecode.verbose
true
Print additional information like the Constant Pool and stack map frames (-v).
javaBytecode.showPrivateMembers
true
Show all classes and members including private ones (-p).
javaBytecode.showLineAndLocalVariableTables
true
Show line number and local variable debug tables (-l).
javaBytecode.autoSyncCursor
true
Automatically highlight matching bytecode instructions when moving the cursor in a .java file.
javaBytecode.outputDirectories
[...]
Glob patterns for compiled class output directories (Maven, Gradle, etc.).
Commands
Command
Title
Context
javaBytecode.showCurrentFileBytecode
Java: Show Bytecode
Editor title bar when editing a .java file
javaBytecode.refreshTree
Refresh Classes
View header in the Java Bytecode Explorer
javaBytecode.toggleVerbose
Toggle Verbose (Constant Pool)
Editor title bar when viewing bytecode
javaBytecode.togglePrivateMembers
Toggle Private Members
Editor title bar when viewing bytecode
javaBytecode.toggleLineNumbers
Toggle Line Number Tables
Editor title bar when viewing bytecode
Building & Contributing
The extension is bundled with Bun and esbuild for near-instant builds (< 50ms):
# 1. Install dependencies
bun install
# 2. Build extension
bun run build
# 3. Watch mode during development
bun run watch
# 4. Package VSIX for distribution
bunx vsce package
Press F5 in VS Code to launch the Extension Development Host and test your changes.
