First, it’s worth noting that by “slow,” we’re talking about something that can take tens of nanoseconds. For trivial native methods, in 2010 I measured calls at an average 40 ns on my Windows desktop, and 11 ns on my Mac desktop. Unless you’re making many calls, you’re not going to notice. That said, calling … Read more
Minimal runnable example Main.java public class Main { public native int square(int i); public static void main(String[] args) { System.loadLibrary(“Main”); System.out.println(new Main().square(2)); } } Main.c #include <jni.h> #include “Main.h” JNIEXPORT jint JNICALL Java_Main_square( JNIEnv *env, jobject obj, jint i) { return i * i; } Compile and run: sudo apt-get install build-essential openjdk-7-jdk export JAVA_HOME=’/usr/lib/jvm/java-7-openjdk-amd64′ … Read more
For certain versions of Java, you can check the bitness of the JVM from the command line with the flags -d32 and -d64. $ java -help … -d32 use a 32-bit data model if available -d64 use a 64-bit data model if available To check for a 64-bit JVM, run: $ java -d64 -version If … Read more
You need a 64-bit trio: 64-bit OS 64-bit Java 64-bit Eclipse