Java 9 High Performance

Tiered Attribution

The first and foremost change providing compiler improvement is related to Tiered Attribution (TA). This change is more related to lambda expressions. At the moment, the type checking of poly expression is done by type checking the same tree multiple times against different targets. This process is called Speculative Attribution (SA), which enables the use of different overload resolution targets to check a lambda expression.

This way of type checking, although a robust technique, adversely affects performance significantly. For example, with this approach, n number of overload candidates check against the same argument expression up to n * 3 once per overload phase, strict, loose, and varargs. In addition to this, there ...