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pliz discirbe the concept of threading and packeage.
and also give me example

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Hi,
Please visit the link. There you will find almost all your JAVA related questions answered.
http://www.coders2020.com/java-interview-questions
However a sample example for creating threads is as follows:
It uses the Runnable interface to implement a thread (most preferable way to implement a thread)

  1. // Create multiple threads.
  2. class NewThread implements Runnable {
  3.   String name; // name of thread
  4.   Thread t;
  5.  
  6.   NewThread(String threadname) {
  7.     name = threadname;
  8.     t = new Thread(this, name);
  9.     System.out.println("New thread: " + t);
  10.     t.start(); // Start the thread
  11.   }
  12.  
  13.   // This is the entry point for thread.
  14.   public void run() {
  15.     try {
  16.       for(int i = 5; i > 0; i--) {
  17.         System.out.println(name + ": " + i);
  18.         Thread.sleep(1000);
  19.       }
  20.     } catch (InterruptedException e) {
  21.       System.out.println(name + "Interrupted");
  22.     }
  23.     System.out.println(name + " exiting.");
  24.   }
  25. }
  26.  
  27. class MultiThreadDemo {
  28.   public static void main(String args[]) {
  29.     new NewThread("One"); // start threads
  30.     new NewThread("Two");
  31.     new NewThread("Three");
  32.  
  33.     try {
  34.       // wait for other threads to end
  35.       Thread.sleep(10000);
  36.     } catch (InterruptedException e) {
  37.       System.out.println("Main thread Interrupted");
  38.     }
  39.  
  40.     System.out.println("Main thread exiting.");
  41.   }
  42. }


Answer by: indi.anupam
 
 

An example for package as follows..

  1. // A simple package
  2. package MyPack;
  3.  
  4. class Balance {
  5.   String name;
  6.   double bal;
  7.  
  8.   Balance(String n, double b) {
  9.     name = n;
  10.     bal = b;
  11.   }
  12.  
  13.   void show() {
  14.     if(bal<0) 
  15.       System.out.print("-->> ");
  16.     System.out.println(name + ": $" + bal);
  17.   }
  18. }
  19.  
  20. class AccountBalance {
  21.   public static void main(String args[]) {
  22.     Balance current[] = new Balance[3];
  23.  
  24.     current[0] = new Balance("K. J. Fielding", 123.23);
  25.     current[1] = new Balance("Will Tell", 157.02);
  26.     current[2] = new Balance("Tom Jackson", -12.33);
  27.  
  28.     for(int i=0; i<3; i++) current[i].show();
  29.   }
  30. }

Another example describing the relation and access control between different packages...
  1. package p1;
  2.  
  3. public class Protection {
  4.   int n = 1;
  5.   private int n_pri = 2;
  6.   protected int n_pro = 3;
  7.   public int n_pub = 4;
  8.  
  9.   public Protection() {
  10.     System.out.println("base constructor");
  11.     System.out.println("n = " + n);
  12.     System.out.println("n_pri = " + n_pri);
  13.     System.out.println("n_pro = " + n_pro);
  14.     System.out.println("n_pub = " + n_pub);
  15.   }
  16. }
  17.  
  18. class Derived extends Protection {
  19.   Derived() {
  20.     System.out.println("derived constructor");
  21.     System.out.println("n = " + n);
  22.  
  23. //  class only
  24. //  System.out.println("n_pri = " + n_pri);
  25.  
  26.     System.out.println("n_pro = " + n_pro);
  27.     System.out.println("n_pub = " + n_pub);
  28.   }
  29. }
  30.  
  31. class SamePackage {
  32.   SamePackage() {
  33.     Protection p = new Protection();
  34.     System.out.println("same package constructor");
  35.     System.out.println("n = " + p.n);
  36.  
  37. //  class only
  38. //  System.out.println("n_pri = " + p.n_pri);
  39.  
  40.     System.out.println("n_pro = " + p.n_pro);
  41.     System.out.println("n_pub = " + p.n_pub);
  42.   }
  43. }

  1. package p2;
  2.  
  3. class Protection2 extends p1.Protection {
  4.   Protection2() {
  5.     System.out.println("derived other package constructor");
  6.  
  7. //  class or package only
  8. //  System.out.println("n = " + n);
  9.  
  10. //  class only
  11. //  System.out.println("n_pri = " + n_pri);
  12.  
  13.     System.out.println("n_pro = " + n_pro);
  14.     System.out.println("n_pub = " + n_pub);
  15.   }
  16. }
  17.  
  18. class OtherPackage {
  19.   OtherPackage() {
  20.     p1.Protection p = new p1.Protection();
  21.     System.out.println("other package constructor");
  22.  
  23. //  class or package only
  24. //  System.out.println("n = " + p.n);
  25.  
  26. //  class only
  27. //  System.out.println("n_pri = " + p.n_pri);
  28.  
  29. //  class, subclass or package only
  30. //  System.out.println("n_pro = " + p.n_pro);
  31.  
  32.     System.out.println("n_pub = " + p.n_pub);
  33.   }
  34. }

  1. // Demo package p1.
  2. package p1;
  3.  
  4. // Instantiate the various classes in p1.
  5. public class Demo {
  6.   public static void main(String args[]) {
  7.     Protection ob1 = new Protection();
  8.     Derived ob2 = new Derived();
  9.     SamePackage ob3 = new SamePackage();
  10.   }
  11. }

  1. // Demo package p2.
  2. package p2;
  3.  
  4. // Instantiate the various classes in p2.
  5. public class Demo {
  6.   public static void main(String args[]) {
  7.     Protection2 ob1 = new Protection2();
  8.     OtherPackage ob2 = new OtherPackage();
  9.   }
  10. }

All the examples are from JAVA 2 Complete Reference by Herbert Schildt....


Answer by: indi.anupam
 
 

prateek, get back to us if u need something more.


Answer by: coders2020
 
 

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