current thread not owner

[Jigar Naik]

Hi i have created on small application and want to use threading the small application prints the current thread busy (jboss server) which need to be printed after every few interval and should never end printing

Code :

  
import java.net.*;
import java.io.*;
 
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
 
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
 
import sun.rmi.runtime.GetThreadPoolAction;
//Screen Scrape >>> <a href="http://localhost:8080/status?full=false" target="_blank" rel="nofollow">http://localhost:8080/status?full=false</a>
 
public class Scrapper implements Runnable{
private static final String CONNECTOR = "jk-8009";
public static void main(String []args){

Scrapper sc = new Scrapper();
Thread t = new Thread(sc);
for(; :wink: {
t.start();
try {
t.wait(10000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}
public void start(){

}
public void run(){
try{
   String data = "http://localhost:8080/status?XML=true";  
   URL url = new URL(data);
   HttpURLConnection conn = (HttpURLConnection)url.openConnection(); 
   //Get the response
   BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
       DocumentBuilder docBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder(); 
       Document doc = docBuilder.parse(new InputSource(rd));
         
       NodeList connectors = doc.getElementsByTagName("connector");
       int size = connectors.getLength();
       for( int i = 0; i < size ; i++){ 
       Element connector = (Element)connectors.item(i);
       final String name = connector.getAttribute("name");
       if(CONNECTOR.equals(name)){
       NodeList threadInfoList = connector.getElementsByTagName ("threadInfo");
       Element threadInfo = (Element)threadInfoList.item(0);
       String currentThreadBusyValue = threadInfo.getAttribute("currentThreadsBusy");
       System.out.println (" # of busy threads --> " + currentThreadBusyValue);
       break; 
       }
       }
       rd.close();
}catch(Exception e){
e.printStackTrace();
}
}
}

ERROR :

  
Exception in thread "main" java.lang.IllegalMonitorStateException: current thread not owner
at java.lang.Object.wait(Native Method)
at Scrapper.main(Scrapper.java:25)
 # of busy threads --> 1
 

[Ramesh Shankar]

t.wait() should come inside a synchronized block

[Jigar Naik]

I have replaced t.wait with t.sleep(1000);

at Console :

 # of busy threads --> 1
Exception in thread "main" java.lang.IllegalThreadStateException
at java.lang.Thread.start(Thread.java:571)
at Scrapper.main(Scrapper.java:23)

[Jigar Naik]

Can anybody tell me what modification should i do in the following progame to keep the System.out.println line executing again and again agter the interval of 1000 ms ???

   
public class TestThread implements Runnable{
public void run(){
System.out.println("Hello from a thread");
}
public static void main(String[] args){
(new Thread(new TestThread())).start();
}
}
 

[Nitesh Kant]

public class TwoThreads implements Runnable {
    public void run() {
        while(true) {
            try {
                Thread.sleep(1000);
                System.out.println("Hello from a thread");
            } catch(InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
 
    public static void main(String[] args) {
        new Thread((new TwoThreads())).start();
    }
}

[Paul Sturrock]

Moving to threads forum...