10 Things You Can Safely Modify Inside a JAR File

A practical list of bytecode-level edits that the JVM verifier will always accept — strings, integers, floats, booleans, access modifiers, annotations, debug metadata, and more.

Why Some Edits Are Safe and Others Aren't

1. String Constants

2. Integer Constants

3. Float and Double Constants

4. Long Constants

5. Boolean Flags (Flipping True/False)

6. Access Modifiers

7. Static Final Field Values (ConstantValue)

8. Annotation Values

9. Debug Metadata

10. Local Variable and Parameter Names

What's Unsafe: Don't Touch These

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