Question

This might sound weird but I am struggling with this bug for past 2 days.

1. I have a boolean array in java that is initialised using a Random boolean generator.

2. After that the boolean array is acted upon by a function in C (called using JNI) and the modified boolean array is returned to java. When I hand over the boolean array to C, it is converted to unsigned char and converted back to jbooleanArray before being handed back to java.

3. Now I run the following code (there is a for loop over i):

   if(chosen_packet[i] == false)
   {
        pkt.first[i] = 0;
        System.out.print(chosen_packet[i]);
   }
   if(chosen_packet[i] == true)
   {
        pkt.first[i] = 1;
        System.out.print(chosen_packet[i]);
   }
   

The problem is that sometimes when chosen_packet[i] is true it still does not enter the second if condition. This happens sometimes and sometimes the code works just fine. When I print chosen_packet[i] in such a case it is printed as true yet it does not enter the second if condition. What could be the possible reason for this seeming corruption of the boolean array ?

EDIT: This is how I convert the boolean array to unsigned char in C:

 jboolean *element = (*env)->GetBooleanArrayElements(env,chosen_packet,0);
 for(j = 0; j < sz; j++)
          src_pkt[j] = (unsigned char)element[j];

This src_pkt is acted upon and then I convert it back to jboolean .

EDIT2: This is how I convert the unsigned char array back to jboolean:

 jbooleanArray arr = (*env)->NewBooleanArray(env,sz);
 (*env)->SetBooleanArrayRegion(env,arr,0,sz,src_pkts);
 (*env)->DeleteLocalRef(env,arr);

Answer 1

It’s normal that if the boolean is true it does not enter in the first if since you are checking for it to be false in its condition.

Your code can be simplified to (you should use if/else instead of two if checking for the different conditions).

if (chosen_packet[i]) {
    pkt.first[i] = 1;
} else {
    pkt.first[i] = 0;
}
System.out.print(chosen_packet[i]);

or even

pkt.first[i] = chosen_packet[i] ? 1 : 0;
System.out.print(chosen_packet[i]);

Edit

If your program does not enter the second if, it means that the the var chosen_packet[i] is not true, you could use a debugger to verify what is the real value.

As stated by fredcrs, are you sure that chosen_packet[i] is of type boolean?