Warning about single underscore identifier

Roel Spilker r.spilker at gmail.com
Mon Jul 29 06:59:10 PDT 2013

Hi all,

If I compile a java program containing an identifier consisting of just a
single underscore using the java 8 compiler, I get the following warning:

warning: '_' used as an identifier
(use of '_' as an identifier might not be supported in releases after Java
SE 8)

I suspect this is to allow for scalaesc parameters in lambdas.

Can someone confirm my suspicion? Is this still relevant or is this a
left-over from an early design? Is there a valid reason to not support '_'
for all identifiers, or can it be only restricted for identifiers inside
lambdas, and therefore guaranteed new code, to maintain backwards source


More information about the lambda-dev mailing list