Pervius

Modern Java decompiler and bytecode editor.

Vineflower decompilation · ClassForge bytecode rewriting · Native Rust UI

Features · Requirements · Build · Shortcuts · 中文

Features

Decompilation

Powered by Vineflower, with both batch JAR decompilation and on-demand single-class decompilation. Small JARs are fully decompiled upfront; large JARs decompile class-by-class on demand. Vineflower progress is parsed in real time and tracked per class. Results are cached by the JAR's SHA-256, so reopening never triggers a rebuild. Kotlin classes are auto-detected and emitted as .kt with original line-number mapping preserved.

Bytecode Editing

Structured .class editor: the left pane navigates class info, fields, and methods; the right pane provides the matching editor. Access flags, inheritance, annotations, and descriptors are all editable, along with method instructions. On save, ClassForge (built on ASM 9.7) handles constant-pool rebuilding, StackMapTable recomputation, and max_stack / max_locals. Untouched methods are byte-copied; only modified methods trigger frame recomputation.

Tri-View

Every .class can be toggled between three views with Tab:

• Decompiled view — syntax-highlighted Java / Kotlin source, read-only
• Bytecode view — structured editor
• Hex view — interactive hex inspector

Non-.class text files (XML, YAML, JSON, etc.) are editable directly with syntax highlighting; binary files open in the hex view.

Code Navigation

Ctrl+Click (macOS Cmd+Click) jumps to class, method, or field definitions. Supports import resolution, same-package inference, and wildcard matching. Ctrl+Click on a method declaration triggers Find Usages, searching all references automatically.

Global Search

Double Shift opens the search panel across every decompiled source, with regex and case-sensitivity support. Results stream back grouped by class with line-level highlighted previews; double-click to jump. The index is built in the background after decompilation completes and never blocks the UI.

Archive Browsing

The left-hand resource tree lists JAR contents and supports jar, zip, war, and ear. Type to filter (Speed Search) with filtering computed on a background thread. Modified and decompilation states are reflected in real time. Drag-and-drop opening and a recent-files list are supported.

Export

• Export JAR (Ctrl+Shift+S) — writes modifications back and produces a new archive
• Export decompiled sources (Ctrl+Shift+E) — exports .java / .kt to a directory, preserving the package layout

Requirements

• JAVA_HOME configured

Vineflower and ClassForge are bundled and extracted to the data directory on first launch. To override, drop a JAR with the same name next to the executable (highest priority).

Build

cargo build --release

ClassForge and Vineflower are embedded via include_bytes!, so no extra JAR copying is needed.

Build ClassForge (only required after modifying ClassForge sources):

cd classforge
./gradlew jar    # Windows: .\gradlew.bat jar

Copy the resulting JAR into crates/pervius-java-bridge/libs/, overwriting the file of the same name, then rebuild Rust.

cargo run --release

Shortcuts

Shortcut	Action
Ctrl+O	Open archive or single file
Ctrl+S	Save
Ctrl+F	Find
Double Shift	Global search
Ctrl+Click	Go to definition / Find Usages
Tab	Switch view
Alt+1	Toggle resource tree
Ctrl+Shift+S	Export JAR
Ctrl+Shift+E	Export decompiled sources
Ctrl+,	Settings

All shortcuts can be customized in Settings.

Credits

• Vineflower — Java decompilation engine
• ASM — Java bytecode manipulation framework
• egui — Rust immediate mode GUI
• tree-sitter — syntax highlighting

License

MIT