Pointers

Question

Hello Everybody,
I am new to JNI....
Following is the code, am having the problem with pointers if somebody helps it will gr8.
Ptr.java
class Ptr
private native int Add(int a, int b);
public static void main(String args[])
int a=5,b=6;
for(int i=1;i<=3;i++)
Ptr x = new Ptr();
a = x.Add(a,b);
System.out.println(" In Java ");
System.out.println(" a =" +a);
static
System.loadLibrary("Ptr");
Ptr.c
#include<jni.h>
#include<stdio.h>
#include "Ptr.h"
JNIEXPORT jint JNICALL Java_Ptr_Add(JNIEnv *env, jobject obj, jint x, jint y)
jint a,b;
jint c;
jfieldID fid;
jclass cls = (*env)->GetObjectClass(env,obj);
printf(" In C\n");
//fid = (*env)->GetFieldID(env,cls,"a","Ljava/lang/String;");
a=(env)->GetIntField(env,obj,&x);
printf(" x got \n");
b=(env)->GetIntField(env,obj,&y);
printf(" y got \n");
a=(*a+*b);
printf("%d",a);
//x=40;
//c=(*env)->SetIntField(env,obj,x,a);
return ((*env)->SetIntField(env,obj,x,a));
//(*env)->SetIntField(env,obj,x,a);
I wanted to update the value of 'a' in the Ptr.java file....How can I use pointers so that 'a' value be changed....it should have to have the sum of numbers...
Please Help Me
svr

Answer 1

1. You are missing error checking on the JNI method calls
2. You can't access local variables regardless of what you do. The methods you are using are for accessing member variables (members of the class.) And if you were doing error checking after each call that would be obvious.