Bytecode recap

To start with, let's recap on what we know about bytecode.

To get from source code to machine runnable code. The Java compiler produces bytecode. This is either interpreted by the JVM or re-compiled by the Just-in-time compiler.

When it's interpreted, the bytecode is turned into machine code on the fly and executed. This happens each time the bytecode is encountered but he JVM.

When it's Just-in-time compiled, the JVM compiles it directly into machine code the first time it's encountered and then goes on to execute it.

Both happen at run-time but Just-in-time compilation offer lots of optimizations.

So, Java bytecode is the intermediate representation between source code and machine code.

Note

As a quick side bar: Java's JIT compiler has enjoyed a great reputation over the years. But going back full circle to our introduction, it was John McCarthy that first wrote about JIT compilation way back in 1960. So it's interesting to think that it's not just lambda support that was influenced...