DISCLAIMER: These notes are from the defunct k8 project which precedes SquirrelJME. The notes for SquirrelJME start on 2016/02/26! The k8 project was effectively a Java SE 8 operating system and as such all of the notes are in the context of that scope. That project is no longer my goal as SquirrelJME is the spiritual successor to it.
I decided to upgrade my OpenJDK 8 installation on Debian, compiling the package took 16.2 hours. Quite a delay. I also upgraded my local QEMU to 2.4 and I decided I could use the i386 Java VMs also so I installed that. The i386 VMs could be used for testing, even though they are emulated on this PowerPC system. Now I have 1.8, build 66 and I just need to test building k8 with it to see how it is.
And it does not work, which means 16 hours wasted. Zero works but it is rather slow, JamVM is much better.
Perhaps I may be able to patch the shared library and add the symbol that I
need. The error being
javac: relocation error: /usr/lib/jvm/java-8-openjdk-
powerpc/jre/lib/ppc/libjava.so: symbol JVM_GetResourceLookupCacheURLs, version
SUNWprivate_1.1 not defined in file libjvm.so with link time reference. Seems
JamVM lacks that symbol and I am not exactly sure how it would handle it if I
changed the way it is patched and such. A short patch could probably
LD_PRELOAD, but that might mess up under some environments that depend on it
An alternative would be to compile my own JamVM with said library and use that instead.
Cannot get this to work, so I am going to take the knowledge that I have working on k8 and write my own libjvm.so which just translates the bytecode to C, passes it to the GCC, and then dlopens the generated class library. The good thing is that adding support for a new VM is simple as I just need to change the configuration and add an extra libjvm.so.
PalmOS does have a C compiler for it called OnBoard C, however compared to say GCC it is a bit crippled. It would be interesting though to generate C source code from Java classes and then use the compiler on it to generate code. OnBoard C only generated m68k code however.