InnnerClassLambdaMetafactory heavily used ASM.Type. The general purposes are:
- getting parameter size,
- getting correct opcode for LOAD and RETURN operation,
- making Type's String description,
- generating proper conversions from TypeConvertingMethodAdapter.
All that gives a significant performance overhead.
Attached webrev contains improvements where all actions above are implemented using standard "Class<?>" structures.
As result we get +3% - +10% performance improvement to lambda linkage.