Java Threads Tutorial | Multithreading In Java Tutorial | Java Tutorial For Beginners | Edureka

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Java String
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What is a Java Thread?
Thread Lifecycle
Creating a Thread
Main Thread
Multi Threading
Thread Pool

Thread is a lightweight sub process
Contains a separate path of execution
A thread is created & controlled by the java.lang.Thread class
It is the smallest independent unit of a program
Every Java program contains at least one thread

Java Thread Life-Cycle

Thread Lifecycle
New
Runnable
Running
Terminated
Waiting
A Java thread can lie only in
one of the shown states at
any point of time

Thread Lifecycle
New
Runnable
Running
Terminated
Waiting
A new thread begins its life cycle in this state & remains here until the program
starts the thread. It is also known as a born thread.
New
Once a newly born thread starts, the thread comes under runnable state. A thread
stays in this state is until it is executing its task.
Runnable
In this state a thread starts executing by entering run() method and the yield()
method can send them to go back to the Runnable state.
Running
A thread enters this state when it is temporarily in an inactive state i.e it is still
alive but is not eligible to run. It is can be in waiting, sleeping or blocked state.
Waiting
A runnable thread enters the terminated state when it completes its task or
otherwise terminates.
Terminated

Creating a Thread

public interface Runnable
public class Thread
extends Object
implements Runnable
Creating A Thread
A thread in Java can be created using two ways
Runnable InterfaceThread Class

1. Create a Thread class
2. Override run() method
3. Create object of the class
4. Invoke start() method to
execute the custom threads run()
public class MyThread extends Thread {
public void run(){
System.out.println(“Edureka’s Thread…");
}
public static void main(String[] args) {
MyThread obj = new MyThread();
obj.start();
}

1. Create a Thread class implementing
Runnable interface
2. Override run() method
3. Create object of the class
4. Invoke start() method using the
object
public class MyThread implements Runnable {
public void run(){
System.out.println(“Edureka’s Thread…");
}
public static void main(String[] args) {
Thread t = new Thread(new MyThread());
t.start();
}

Runnable InterfaceThread Class vs

Runnable InterfaceThread Class vs
✓ Each Thread creates its unique object ✓ Each Thread creates its unique object
✓ More memory consumption ✓ More memory consumption
✓ A class extending Thread class can’t extend any
other class
✓ Along with Runnable a class can implement any
other interface
✓ Thread class is extended only if there is a need
of overriding other methods of it
✓ Runnable is implemented only if there is a need of
special run method
✓ Enables tight coupling ✓ Enables loose coupling

Java Main Thread

Java Main Thread
Subtitle for arrow graphic
It is executed whenever a Java program starts
Every program must contain this thread for its execution to take place
Java main Thread is needed because of the following reasons
Main thread is the most important thread of a Java Program
2. It must be the last thread to finish execution i.e when the main thread stops program terminates
1. From this other “child” threads are spawned

Java Main Thread
Main Thread Other Demon Threads
Child Thread A Child Thread B
Child Thread C
JVM
start() start()
start()start()
start()

Multi Threading In Java

Multi – Threading
Multi threading is the ability of a program to run two or more threads concurrently, where each thread can handle
a different task at the same time making optimal use of the available resources
Main Thread Main Thread Main Thread
Main Thread
start() start() start()
switching switching

Thread Pool

Task Task Task Task Task
Application
Queue
Thread
Thread
ThreadTask Finished
Thread
AssignmentNew Task
Thread Pool
Java thread pool manages the pool of worker threads and contains a queue that keep the
tasks waiting to get executed

Thread Methods
Creating Multiple
Threads
Joining Threads Thread.sleep()
Inter Thread
Communication
Daemon Thread

Java Threads Tutorial | Multithreading In Java Tutorial | Java Tutorial For Beginners | Edureka

Java Threads Tutorial | Multithreading In Java Tutorial | Java Tutorial For Beginners | Edureka

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