Linker Error: leJOS NXJ HelloWorld complains 32 bit JVM unsupported

32-bitjava

I trying to get started using leJOS NXJ to develop in Java for my Mindstorms NXT. I've installed Oracle's Java 8 JDK, Eclipse and leJOS NXJ on my Macbook Pro running Mountain Lion. When I try to link the HelloWorld tutorial program I get the following error:

src> nxjlink -o HelloWorld.nxj HelloWorld
Error: This Java instance does not support a 32-bit JVM.
Please install the desired version.

Is there a 32-bit Java Virtual Machine for OS X?

Best Answer

Apple's Java 6 JDK, pre-installed in Mountain Lion, does support 32-bit targets.

I modified my .bashrc file which is sourced by my .profile to set 

# for leJOS                                                                   
export NXJ_PATH=/Users/Shared/leJOS_NXJ_0.9.1beta-3
export PATH=$PATH:$NXJ_PATH/bin
## Point leJOS NXJ at Apple's Java 6 JDK                                        
export LEJOS_NXT_JAVA_HOME=/System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home
#export LEJOS_NXT_JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.7.0_76.jdk/Contents/Home

This points leJOS at Apple's Java 6 JDK instead of at Oracle's Java 7 or Java 8 JDK, which resolves the 32-bit linker error. I have successfully gotten HelloWorld to run on my NXT using the command-line interface to leJOS, however I still need to figure out how to set things up so that I can use Eclipse to write leJOS code.

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