How to build a port with java-7 and maven?

[Dmitry Sivachenko]

Hello,

Imagine a port which requires Java 7 (say, devel/hadoop2).
It uses maven build system.

Since default java version is Java 8, build cluster will install Java 8 package as maven's dependency (since maven does not require specific java version).

After that, despite JAVA_VERSION=1.7 in hadoop2 port, maven will use Java8 to compile hadoop's sources.

What is the proper way to fix that?

Thanks!