Have you looked at Eclipse Compiler for Java? It appears to be an active project. The appeal of Java was in the write once, run everywhere sales pitch. That's

Have you looked at Eclipse Compiler for Java? It appears to be an active project. The appeal of Java was in the write once, run everywhere sales pitch. That's why enterprise software used it widely, running on Solaris, AIX, HPUX and Windows. OSS were less willing adopters - many other choices without the proprietary overhang. Since Oracle acquired Sun and with it Java, it is seen to be even more proprietary and AIX and HPUX installations are petering out. So there is less incentive to maintain a compiler when Oracle makes various unexpected changes to the language and the licensing terms. LibreOffice (derived from StarOffice - Sun) is an exception due to two factors. First of all it was created by Sun and as a competitor to MS Office. These days it runs on Windows, OS X and Linux mostly - three incompatible environments which are bridged by JVM.