Introduction to threads in Java

A thread, by definition is a light weight process. They are used to increase functionality and performance by performing multiple tasks at the same time, i.e. concurrently. There are two methods for implementing threads in Java,

• Implementing an interface
• Extending a class

I'd assume that the reader is familiar with the basic Object Oriented Paradigm concepts and understands terms like 'extending', 'interface' and 'class'. Now you may start wondering why are there two ways to create threads. This is because if a class is already an inherited class of some class other than 'Thread', then it cannot extend 'Thread' because multiple inheritance is not allowed in the Java programming language. So, in such cases we use 'Runnable' interface instead.

Now, let's jump onto the coding part on how to actually create threads. The first method is to extend or inherit the 'Thread' class. The 'Thread' class is defined in the package java.lang, which needs to be imported. Take a look at the code below to get a better idea,

Code:

 import java.lang.*;
  
 public class myExample extends Thread
  {
      public void run()
      {
      ....
      }
  }
  

The other way to do this is to implement 'Runnable', as shown below,

Code:

import java.lang.*;
  public class myExample implements Runnable
  {
      Thread T;
      public void run()
      {
      ....
      }
  }
  

Notice that both the methods make use of the 'run()' function, which is responsible for the actions of the thread. The 'Runnable' interface actually is nothing but a class containing only one abstract method, 'public abstract void run();'. Remember an interface only provides a design framework upon which classes can be implemented. It is also interesting to note that actually the 'Thread' class also implements the 'Runnable' interface.

 

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Is it in any waiz related to the above topic ???????? ......

Hey guys don't get furious on readin this !!! I m just tryin to be funny !!!!

Any waiz, good work u all are doin !!! KEEP GOIN GUYS !!!

 

Hi Pradeep ,
Can you please illustrate this with greater detail .. taking examples on each of impl., that would help understand the concepts in a practical way ?
thanks .. HS

 

It is better in the long term to use the implements runnable interface as this will make your code more extendible in the future as you can also have threads that subclass other classes other than just Thread. What is not mentioned is that the thread has a shared state from the calling class which brings in the Synchronized keyword when changing the state.

 

hey pradeep don't you think that java.lang is provided by default....it doesn't need to be imported on any program....

 

In java we declare thread in two ways
There are two methods for implementing threads in Java,

• Implementing an interface
• Extending a class

 

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