Files you upload for decompilation are processed in a secure, isolated server environment and permanently deleted after the decompiled source is returned. Nothing is stored or retained. After decompilation, the [[toolsCodeExplainer:AI Code Explainer]] can give you a plain-English breakdown of what the reconstructed code does: useful when the original variable names were lost in compilation and the logic is hard to follow.

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Decompile compiled Java .class and .jar files back into readable source code. Choose between proven engines like CFR, JADX, Vineflower, Procyon, or JD-Core and recover clean Java in seconds. No local setup, no configuration headaches, just upload your file and inspect the bytecode instantly.

Java Decompilerv1.0.0

Java Decompiler

Upload a compiled .class or .jar file to recover readable Java source code. All uploaded files must be the same type: either .class or .jar.

Upload File

Drop a .class or .jar file here

Click or drop a file · validated by extension

File Info

Type

—

Size

—

Batch Capacity

0/1 slot used· Upgrade for batch mode

Upload a file to configure the decompiler engine

5 Decompiler Engines

Choose from CFR, JADX, Vineflower, Procyon, or JD-Core depending on your Java version and decompilation needs.

.class & .jar Support

Upload individual .class files for direct source output, or .jar archives which return a downloadable ZIP of all decompiled classes.

Secure Processing

Files are processed in isolated sandboxes and deleted immediately after decompilation. Nothing is retained.

Guide

How to Decompile a Java File

Upload your .class or .jar file

Drag and drop or click to browse. Files up to 1MB are supported during the testing phase.

Choose a decompiler engine

Select from CFR, JADX, Vineflower, Procyon, or JD-Core depending on your Java version and needs.

Click Decompile

Processing typically takes under 5 seconds. .class files return readable source directly; .jar files download as a ZIP.

Copy or download your source

Copy individual classes to clipboard or download the full decompiled archive to your machine.

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Use Cases

Who Uses a Java Decompiler?

Security Researchers

Audit third-party JARs and dependencies for vulnerabilities or malicious code without access to source.

Developers

Recover lost source files, inspect library internals, or understand undocumented APIs.

Students & Educators

Study how compiled bytecode relates to Java syntax: a practical tool for learning the JVM.

Reverse Engineers

Analyse legacy software, understand obfuscated code, or port old applications to modern frameworks.

QA & DevOps Teams

Verify that production builds match expected source and that no unauthorized code was introduced.

Open Source Contributors

Inspect upstream libraries to write better patches, bug reports, or compatibility layers.

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Comparison

Endless Forge vs Other Java Decompilers

5 engines, browser-based, and no registration required.

Feature

Other Toolsaverage

Endless Forge✦ This website

5 decompiler engine choices

Yes

.jar to ZIP output

Yes

No install required

Sometimes

5 engines

Files deleted after processing

Sometimes

Yes

Supports modern Java versions

Yes

Free to use

Limited

Yes

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Recover Java Source Code

The Endless Forge Java Decompiler gives you access to five of the most respected open-source decompiler engines in one place. Whether you need CFR's reliability, JADX's Android compatibility, or Vineflower's modern Java support, switch engines with one click and compare results without leaving the page.

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Explore

More Developer Tools

Code Formatter

Auto-format messy code with consistent indentation and style rules.

AI code explainer V1

Paste any code snippet and get a plain-English explanation of what it does.

AI code optimization

Refactor and optimize your code for performance and readability using AI.

AI Code Comment Remover

Strip all comments from your codebase cleanly without touching logic.

Regex Tester

Test and debug regular expressions with live match highlighting, capture group display, replace mode, and a built-in cheat sheet.

Base64 Encoder / Decoder

Encode text or files to Base64 and decode Base64 strings back to plain text, with URL-safe mode and image preview support.

JSON Formatter

Beautify and pretty-print raw JSON with configurable indentation, syntax highlighting, and instant error detection.

Simple Text Analyzer

Analyze word count, reading time, sentiment, and readability score in a clean and simple way.

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FAQ

Frequently Asked Questions

Each engine has different strengths. CFR is reliable for most Java versions. JADX excels at Android APKs. Vineflower (Quiltflower fork) handles modern Java well. Procyon is solid for older bytecode. JD-Core is fast for quick inspections.

Yes, but obfuscated code will produce decompiled output with meaningless variable and class names. The logic is recovered but human readability depends on how aggressively the code was obfuscated.

Modern Java decompilers are highly accurate at reconstructing the logic and structure of the original code. The decompiled output correctly reproduces all method logic, class hierarchies, field declarations, and control flow. Some information is not preserved in bytecode and cannot be recovered: original local variable names, code comments, and precise formatting. Once decompiled, use the Code Formatter to apply consistent Java indentation and style to the output, making it easier to read and work with.

No. Decompiled Java is a best-effort reconstruction. It may not compile without modifications due to synthetic methods, anonymous classes, and bytecode patterns the decompiler approximates.

Files you upload for decompilation are processed in a secure, isolated server environment and permanently deleted after the decompiled source is returned. Nothing is stored or retained. After decompilation, the AI Code Explainer can give you a plain-English breakdown of what the reconstructed code does: useful when the original variable names were lost in compilation and the logic is hard to follow.

5 questions answered

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