Open-source alternatives to Jitescript

Byte Buddy is a runtime code generation and bytecode manipulation library for Java. It provides a fluent API for creating and modifying Java classes during execution, enabling developers to define class structures, methods, and fields programmatically without requiring a compiler or direct bytecode assembly. The library supports agent-based class transformation, allowing loaded classes to be modified during JVM startup or runtime through a Java agent that intercepts class loading. It offers bytecode-level method interception for fine-grained control over method behavior, annotation-based code

Arthas is a Java diagnostic tool and runtime debugger designed for real-time troubleshooting of applications. It functions as a remote diagnostics agent that allows users to inspect the runtime state of a Java process, including its heap objects and classloader hierarchies, without requiring a process restart. The project distinguishes itself through advanced bytecode manipulation capabilities, enabling live class hotswapping and the modification of bytecode in running processes. It supports in-memory source compilation and runtime bytecode decompilation to verify and update logic instantly w

Cojen/Maker is a lightweight, full-featured, low-level dynamic Java class generator designed for ease of use.

Javassist is a bytecode engineering toolkit for analyzing, modifying, and generating Java bytecode and class files. It functions as a bytecode manipulation library that allows for the editing of class files through either direct bytecode access or high-level source code syntax. The project provides specialized tools for the programmatic creation of new Java classes and interfaces during runtime. It includes a dynamic proxy generator for intercepting method calls and a class loader interceptor that automatically modifies class definitions as they are loaded into the Java Virtual Machine. Addi