follwing is the multithreading code in java. i need to use mutex so all thread can use resoursces in synchronized way

 import java.io.FileWriter; import java.io.BufferedWriter; import java.io.IOException; public class ThreadWrite { private static final int num = 3; public static void main(String[] args) { try { FileWriter fw= new FileWriter("out_java.txt", false); // overwrite mode BufferedWriter bw = new BufferedWriter(fw); bw.close(); } catch (IOException e) { e.printStackTrace(); } int num_threads = 5; MyWrite mw[] = new MyWrite[num_threads]; for (int i = 0; i < num_threads; ++i) { mw[i] = new MyWrite("thread " + (i+1)); mw[i].start(); } for (int i = 0; i < num_threads; ++i) { System.out.println(mw[i].th.toString()); for (int j = 0; j < num; ++j) System.out.println(" " + j); try { mw[i].th.join(); } catch (Exception e) {} } System.out.println("end main"); } } class MyWrite implements Runnable { Thread th; private String name; private final boolean append_mode = true; private final int num = 3; MyWrite(String s) { name = s; } public void start() { if (th == null) { th = new Thread(this, name); th.start(); } } @Override public void run() { try { FileWriter fw= new FileWriter("out_java.txt", append_mode); // append mode BufferedWriter bw = new BufferedWriter(fw); bw.append(th.getName() + " : " + th.toString() + " "); for (int j = 0; j < num; ++j) bw.append(" " + j + " "); bw.close(); } catch (IOException e) { e.printStackTrace(); } } }