🫙 JAR Rewriter + ✨ AI Image Generator

Upload a .jar → rewrite .class constant-pool strings & class versions, replace/add/delete entries → repack & download the updated jar. Everything runs locally in your browser. Signed jars: use “strip signatures” on export. Switch tabs for the built-in AI image generator (free, no key).

Drop .jar here or click to browse .jar / .zip accepted · stays on your device · no upload

No jar loaded. Load one to begin.

strip signature files (*.SF, *.RSA, *.DSA, *.EC) on export
compress (DEFLATE level 6); uncheck = STORE

Global class string patch

Find/replace across all .class UTF-8 constants (e.g. rename com/oldname → com/newname, change URLs, log messages). Exact, case-sensitive. Applied to in-memory entries; then Repack.

Tip: any length works — this tool rebuilds the constant pool, so replacements can be shorter or longer. But descriptors must stay valid (e.g. Lcom/a/B;).

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Log

ready.\n

How “update in same jar” works

1. The jar is read entry-by-entry. Unchanged entries are copied byte-for-byte.
2. Only entries you modify/replace/add/delete change.
3. Class string edits rebuild just the constant pool + version header; all bytecode after the pool is preserved exactly.
4. On export you get yourname-updated.jar — replace your original file with it. Manifest ordering and timestamps are preserved where possible.