Something funny happening

Question

Hello folks!
I have this java program:
import java.*;
public class Try {
public String s;
public native String Initialize(String mess);
public native void WriteMessage();
public static void main(String[] args){
Try k = new Try();
k.s = "hello";
String m =k.Initialize(k.s);
System.out.println("m = "+m);
k.WriteMessage();
static{
System.loadLibrary("try");
and the native method is wrapper.c
#include <jni.h>
#include <stdio.h>
#include <iostream.h>
#include "Try.h"
#include "myclass.h"
static myclass *cl;
JNIEXPORT jstring JNICALL
Java_Try_Initialize(JNIEnv *env, jobject obj,jstring s){
// initialize C++ myclass
char message = (char )env->GetStringUTFChars(s,0);
cl = new myclass(message);
(env)->ReleaseStringUTFChars(s,message);
return s;
JNIEXPORT void JNICALL
Java_Try_WriteMessage(JNIEnv *env, jobject obj){
cl->Message();
which calls functions written in C++, myclass.cpp:
#include <string.h>
#include <iostream.h>
#include "myclass.h"
myclass::myclass( char *m ) {
cout << "Message on constructor: " << m << endl;
strcpy( message, m );
void myclass::Message() {
cout<<"you enter the Message method"<<endl;
cout << "Message: ";
cout << message << endl;
When I make the program run, everything works well, EXCEPT that it gives these answers:
Message on constructor: hello
m = hello
you enter the Message method
Message: helmo
Note that I should have hello instead of helmo. Identically, if the word is "bachi", I have this answer: bacii
For words longer than 8 letters, it runs into a VM crash!!!
I think it has something to do with the length of the Strings...
Any answer?
What can I do to correct this mistake?

Answer 1

1. Your C code looks goofy. It copies "message" onto itself.
2. You are misusing the booelan argument to getStringUTF. The argument should be a boolean that is filled in by the call. You should then be checking the boolean to determine whether or not to release memory.
3. You seem to be releasing memory that was - perhaps - allocated to hold the converted message - before you try to print it.