I'm using this tutorial for JNI in Eclipse:
https://www3.ntu.edu.sg/home/ehchua/programming/java/JavaNativeInterface.html#zz-2.6
(I'm using only the part "2.6 JNI in Eclipse").
And until this part of the tutorial:
Run the makefile for the target "all", by right-click on the makefile ⇒ Make >Targets ⇒ Build ⇒ Select the target "all" ⇒ Build
It seemed like everything worked well (meaning- the results were the same as in the tutorial and there were no warning or errors in the "Problems" tab).
But when I did this part, I noticed that the line :
javah -classpath ../bin HelloJNI
was missing from the printing in the console.
Then I continued to the next step of the tutorial- "Step 5: Run the Java JNI Program".
But even though it did print to the console "Hello World!", I noticed that there is an error in the "Problems" tab:
"make: *** No rule to make target `all'. Stop."
Development Environment
+Eclipse IDE for Java Developers (32 bit) Version: Kepler Service Release 2.
+CDT plugin for Eclipse
+Windows 10 64-bit (I use eclipse 32-bit because at some point, the 64-bit eclipse couldn't open and the solution was to use 32-bit eclipse)
makefile
# Define a variable for classpath
CLASS_PATH = ../bin
# Define a virtual path for .class in the bin directory
vpath %.class $(CLASS_PATH)
all : hello.dll
# $@ matches the target, $< matches the first dependency
hello.dll : HelloJNI.o
gcc -Wl,--add-stdcall-alias -shared -o $@ $<
# $@ matches the target, $< matches the first dependency
HelloJNI.o : HelloJNI.c HelloJNI.h
gcc -I"C:\Program Files (x86)\Java\jdk1.8.0_212\include" -I"C:\Program Files (x86)\Java\jdk1.8.0_212\include\win32" -c $< -o $@
# $* matches the target filename without the extension
HelloJNI.h : HelloJNI.class
javah -classpath $(CLASS_PATH) $*
clean :
rm HelloJNI.h HelloJNI.o hello.dll
HelloJNI.c
#include <jni.h>
#include <stdio.h>
#include "HelloJNI.h"
JNIEXPORT void JNICALL Java_HelloJNI_sayHello(JNIEnv *env, jobject thisObj) {
printf("Hello World!\n");
return;
}
HelloJNI.h
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class HelloJNI */
#ifndef _Included_HelloJNI
#define _Included_HelloJNI
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class: HelloJNI
* Method: sayHello
* Signature: ()V
*/
JNIEXPORT void JNICALL Java_HelloJNI_sayHello
(JNIEnv *, jobject);
#ifdef __cplusplus
}
#endif
#endif
HelloJNI.java
public class HelloJNI {
static {
System.loadLibrary("hello"); // hello.dll (Windows) or libhello.so (Unixes)
}
// Declare native method
private native void sayHello();
// Test Driver
public static void main(String[] args) {
new HelloJNI().sayHello(); // Allocate an instance and invoke the native method
}
}
