TLDR: Optimized bytecode refers to the intermediate representation of code generated by a compiler or virtual machine that has been enhanced for code efficiency and code performance. This bytecode is designed to execute faster and use fewer resources while maintaining the program’s correctness. Commonly associated with languages like Java, C Sharp, and Python, optimized bytecode enables high-performance execution across platforms.

https://en.wikipedia.org/wiki/Bytecode

In Java, the Java Compiler translates Java source code into bytecode, which runs on the Java Virtual Machine (JVM). Optimization occurs during this translation or through just-in-time compilation (JIT), which converts bytecode into machine code at runtime. Techniques such as loop unrolling, constant folding, and inlining of frequently called methods are applied to enhance execution speed and reduce memory usage, resulting in optimized bytecode.

https://docs.oracle.com/javase/specs/jvms/se20/html/jvms-2.html

Optimized bytecode is vital for achieving platform independence without sacrificing performance. It ensures that applications run efficiently on different hardware architectures supported by the JVM or CLR (Common Language Runtime). Advanced compiler optimizations like dead code elimination and peephole optimization contribute to faster execution times and lower energy consumption. As bytecode continues to evolve, its optimization remains critical to meeting the demands of modern computing environments.

https://docs.oracle.com/en/java/javase/20/performance/optimizing-code.html