OSGI bundle and threads

Question

I am new in OSGI and i have current aim. I have 10 threads, it's writing their names in a file. After recording thread sleep random 0..1 sec. This all must be a bundle. I create it, but i'm not sure Is this correct. Can any comments?

package helloworld;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import writer.StartThreads;
public class Activator implements BundleActivator {
    public void start(BundleContext context) throws Exception {
        System.out.println("Start Thred!!");

        new StartThreads().Execute();
    }

    public void stop(BundleContext context) throws Exception {
        System.out.println("Goodbye World!!");
    }
}

1

package writer;

import writer.WriterLogs;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

public class StartThreads {

    public static void Execute() {
        BufferedWriter writer = null;
        File textFile = new File("threadLog.txt");
        // if file doesnt exists, then create it
        if (!textFile.exists()) {
            try {
                textFile.createNewFile();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        try {
            writer = new BufferedWriter(new FileWriter(textFile, true));
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        for (int i = 0; i < 10; i++) {
            WriterLogs wrt = new WriterLogs(writer);
            Thread worker = new Thread(wrt);

            worker.setName("Nisha-" + i);
            worker.start();
            try {
                worker.join();
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

        try {
            writer.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

2

package writer;

import java.io.BufferedWriter;
import java.io.IOException;

public class WriterLogs implements Runnable {

    private BufferedWriter writer;

     public WriterLogs(BufferedWriter wr) {
        this.writer = wr;
    }

    @Override
    public void run() {
         try           
         {   
             try {
                 synchronized(this.writer) {
                 this.writer.write(Thread.currentThread().getName() + "\n"); 
                 }

            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

             // set random 0...1 s.
             Thread.sleep((long)(Math.random() * 1000));
             System.out.println(Thread.currentThread().getName());  
         }         
         catch (InterruptedException interruptedException)         
         {             
            /*Interrupted exception will be thrown when a sleeping or waiting                
             * thread is interrupted.                
             */                
             System.out.println( Thread.currentThread().getName() +interruptedException);            
         } 
    }

}

Answer 1

This is not correct. Like Boris the Spider states, when your bundle stops, you should free any resources and stop any processing the bundle was doing. So from the stop method you should somehow signal your threads to stop as soon as they can.

In practice you might get away with letting the code run, but this is definitely not how you should write your code in OSGi (which is what you're asking).