What are Threads? Life Cycle of Thread Types of Priority Ways of Multithreading in Java Example

1. Java
Multithreading in Java
By Nishant S Mevawala

2. What are Threads?
• A piece of code that run in concurrent with other
threads.
• Each thread is a statically ordered sequence of
instructions.
• Threads are being extensively used express
concurrency on both single and multiprocessors
machines.
• Programming a task having multiple threads of
control – Multithreading or Multithreaded
Programming.
2

3. Life Cycle of
Thread

4. Threads
• Java has built in thread support for
Multithreading
• Synchronization
• Thread Scheduling
• Inter-Thread Communication:
currentThread
yield
sleep
start
run
stop
setPriority
getPriority
suspend
resume
• Java Garbage Collector is a low-priority thread

5. Types of Priority
1. Thread.MIN_PRIORITY - 1
2. Thread.MAX_PRIORITY - 10
3. Thread.NORM_PRIORITY - 5

6. Born
Stop
Start
Run
Running
Yield
Sleep
Suspended
Wait
Runnable
Stop
Resume
Wait
Notify
Stop
Dead

7. Ways of Multithreading in Java
•
•
Create a class that extends the Thread class
Create a class that implements the Runnable interface
• 1st Method: Extending the Thread class
class MyThread extends Thread
{
public void run()
{
// thread body of execution
•
•
}
}
Creating thread:
MyThread thr1 = new MyThread();
Start Execution:
thr1.start();

8. Extends Method example
class A extends Thread
{
public void run()
{
for(int i=1;i<=5;i++)
{
System.out.println("t From Thread A: i= "+i);
}
System.out.println("Exit from A");
}
}
class B extends Thread
{
public void run()
{
for(int j=1;j<=5;j++)
{
System.out.println("t From Thread B: j= "+j);
}
System.out.println("Exit from B");
}
}

9. class C extends Thread
{
public void run()
{
for(int k=1;k<=5;k++)
{
System.out.println("t From Thread C: k= "+k);
}
System.out.println("Exit from C");
}
}
class ThreadTest
{
public static void main(String S[])
{
new A().start();
new B().start();
new C().start();
}
}

10. 2nd method: Threads by implementing Runnable
interface
class ClassName implements Runnable
{
.....
public void run()
{
// thread body of execution
}
}
• Creating Object:
ClassName myObject = new ClassName();
• Creating Thread Object:
Thread thr1 = new Thread( myObject );
• Start Execution:
thr1.start();

11. Runnable method Example
class ththead implements Runnable
{
String nm;
Thread t;
public ththead(String st)
{
nm=st;
t=new Thread(this);
}
public void run()
{
for(int i=1;i<=5;i++)
{
System.out.println(nm + ":" +i);
}
}
}

12. class theadrun
{
public static void main(String args[])
{
ththead f1=new ththead("one");
ththead f2=new ththead("Two");
ththead f3=new ththead("Three");
f1.t.start();
f2.t.start();
f3.t.start();
}
}