When compiling JNI related applications, there's a need to access include files and libraries provided by the JRE. This is particularly problematic when using Java invocation interface, as shared libraries, such as libjvm.so, must be found by the dynamic linker.
The typical setup for Java invocation interface looks like this:
The actual library (libjvm.so) is located in $(JAVA_HOME)/jre/lib/amd64/server/ (note the arch-dependend path element incompatible with `uname -m`).
This path should also be added, together with its parent directory, to ld.so.conf, and changed when JVM is switched by java-config.
Having such functionality will help doing JNI work on gentoo system. The functionality required is essentially analogous to what pkg-config does.