SwingWorker - why can't I do this

Question

//StringWorker.java
package myPackage;
import javax.swing.SwingWorker;
public class StringWorker extends SwingWorker<Void, Void>
      public StringWorker(String s)
            s = new String("Today is a sunny day.");
      protected Void doInBackground( ) throws Exception
            return null;
//Driver.java
package myPackage;
public class Driver
      public static void main(String[] args)
           String str = null;
           StringWorker sw = new StringWorker(str);
           sw.execute( );
           while( !sw.isDone( ) )
               System.out.println("Wait...");
           System.out.println(str);
}Output:
Wait...
null

Answer 1

Try this:
//StringWorker.java
package myPackage;
import javax.swing.SwingWorker;
public class StringWorker extends SwingWorker<Void, Void>
      public StringWorker(String[] s)
            s[0] = "Today is a sunny day.";
      protected Void doInBackground( ) throws Exception
            return null;
//Driver.java
package myPackage;
public class Driver
      public static void main(String[] args)
           String[] str = new String[1];
           StringWorker sw = new StringWorker(str);
           sw.execute( );
           while( !sw.isDone( ) )
               System.out.println("Wait...");
           System.out.println(str[0]);
}You have quite some reading to do. Here is something about Strings. Here is something about Objects. No claim as to completeness.