Summary

Adding a way to inject better parameter names to method parameters when the names are not available in the classfiles.

Problem

Classfiles may record method parameters in two forms: either in the MethodParameters or the LocalVariableTable attribute. But if a method has neither of these attributes, then its parameters get a cryptic synthetic name.

An important group of methods that typically get the synthetic parameter names are abstract methods - these don't get debugging info (LocalVariableTable), so unless the classfile was compiled with an explicit "-parameters" option, there are not parameter names for the method.

The parameter names are visible to the API clients using VariableElements.getSimpleName().

Solution

The proposal is to augment com.sun.source.util.JavacTask with a way to set a provider of names for the parameters that don't have names in the classfiles.

Specification

Proposed is ParameterNameProvider which can be plugged into JavacTask and should provide user-friendly parameter names. A spec diff is attached and is also for convenience here:

http://cr.openjdk.java.net/~jlahoda/8217047/specdiff.04/overview-summary.html