Re:Eclipse OpenJ9 – Open-source JVM
by emmelaich on Saturday September 16, 2017 @03:57PM
(#15266419)
They already have a compiler, ECJ, which is included in Eclipse and Tomcat among other things.
does ecj support indy and newer bytecode? I do not think so, but I guess openj9 already supports java 9 bytecode I'm not sure about the actual bytecode version I guess it was 52 on java 8 but I'm not totally sure about it.
I mean ecj is also not included in openj9, so if you want to strip out any openjdk dependency one would need at least a really basic class lib and a compiler (either ecj or anything else), (but I also think it hears that openj9 includes a compiler https://www.youtube.com/watch?v=96XoG6xcnys at the end he only says that they use the class library from openjdk, but he does not say if anything else and it also looks like it only uses that).
ECJ is in Tomcat? What for?
Re:Eclipse OpenJ9 – Open-source JVM
by emmelaich on Saturday September 16, 2017 @04:27PM
(#15266569)
Compiling Java :-)
To be more precise, a compiler is required for JSP, which is a mixture of html and java that is compiled to servlets.
Theoretically you can compile them ahead of time (before deployment) but as far as I can tell no-one does.
Re:Eclipse OpenJ9 – Open-source JVM
by solarengineer on Saturday September 16, 2017 @07:37PM
(#15267354)
Those who want to provide only class files and no jsp code use the JSP pre-compilation approach. The JSP folks get compiled to Java servlet byte code the same as at runtime.
well yes and no. if you don't use anything from the standard class library (that's impossible) than not. what I also guess is that you need a java compiler, since it reads that it uses a ibm created "rom file" that comes from java bytecode.
what the most interesting thing about that vm is, is a shared class cache. which is like a *.so file, if one program loads a library and the library is already in memory another program won't add additional memory to the computer, this is a huge win, especially for memory hungry java applications (this already speeds startup extremly)