JIT Compilation

[Tetsuo Suzuki]

Hello all,
My first question -
I was wondering if the JDK 1.4 now does JIT compilation or if bytecode is still interpreted.
I also wondered -
I went to a presentation of JBuilder 7 and saw that the tool could generate .exe files out of .jar files. Is this a "precompilation" feature from SUN or is it a perk of JBuilder?
thanks much,
tetsuo
the lone wanderer

[Karl Laird]

At the moment all tools that create a windows .exe file for java are proprietory tools from a vendor. Sun does not provide any tools for the creation of platform specific executables as this is seen as counter-intuitive to the 'write-once, run-anywhere' promise of java

[Michael Zalewski]

Every version of Java since JDK 1.2 has had JIT compilation. However, none of the Sun JVM environments will store the compiled version of a .class file in a .jar or in a (Windows) .exe or (Unix) coff.
The JIT got significantly better in JDK 1.3. I am pretty sure that there were improvements made again in 1.4 but I don't know precisely.
If you really want to save the .exe, you can try
The GNU Java Compiler. It's pretty neat stuff. You can mix Java and C++ (without having to do JNI, but you have to use the GNU linker). It can compile .java or .class files. A disadvantage however is that it does not yet fully support Toolkit (which means no Swing).
I do not see where JBuilder has anything more than the standard HotSpot JIT compiler that comes with Sun JDK 1.4. I could be wrong, but I think that when the ads talk about using JIT compiler for fast execution, they just mean that the code is compiled with HotSpot (which is Sun's JIT, and which does not operate outside of memory).