LambdaMetafactory

background knowledge

1. CallSite, a holder of MethodHandler, which is called its target.
2. Field Descriptors: https://docs.oracle.com/javase/specs/jvms/se17/html/jvms-4.html#jvms-4.3.2

LambdaMetafactory

1. Invoke Dynamic: https://jcp.org/en/jsr/detail?id=292
2. lambda表达式反编译后对应的是opcode invokeDynamic
3. invokeDynamic会创建一个CallSite来cache实际调用的方法。
4. 生成lambda对应字节码的时刻：Compile Time or Runtime
5. 例子：Record & String Concatenation

Helpful Command

javap -c -p -v Main