Thread class constructors

• The thread class has overloaded constructors the few important constructors are 

No-argument constructor: 

• Thread t1=new Thread();
• The Thread class was created with the default values of thread properties.

String-argument constructor: 

• Thread t1=new Thread("java");
• Creates a Thread class instance where the thread name will be java. Thread Id and thread priority will get default initialization.

Runnable-argument type constructor: 

• Thread t1=new Thread(r1);
• Let's say ‘r1’ be the object of the Runnable Interface;

Two-argument constructor:

• Thread t1=new Thread(r1,"Quipo");
• Creates the thread class instance with the specified runnable type and specified Thread name. 
• The first argument is the Runnable type and the second argument is the String type.

Thread class methods

Thread class provides various methods as follows:
1. public int getId();

• By invoking this method it receives the ID of Thread.

2. public String getName();

• By invoking this method it receives the name of a Thread.

3. public int getPriority();

• This method returns the priority number of a Thread.

4. public void setName(String name);

• This method is used to set the name of a Thread.

5. public void setPriority(int priorityNum);

• This method is used to set the priority of a Thread.

6. public void start();

• On invoking this method it starts execution of a Thread.
• the start() internally calls the run method of a thread object.

7. public void run();

•  The thread execution begins by calling run().

8. public void stop();

•  The method is used to stop the running thread, on invoking this method the running Thread will be terminated.

9. public static void sleep(long time);

• On invoking this method it pauses the currently running thread for a specified period of time once the time elapsed the thread resumes the execution.

Example for sleep():

package quipoin;
public class Sample extends Thread{
	public void run(){
		System.out.println("Printing even numbers from 1-10");
		for(int i=1;i<=10;i++){
			if(i%2==0){
				System.out.print(i+" ");
			}
			try{
				Thread.sleep(1000);
			}
			catch(InterruptedException e){
				e.printStackTrace();
			}
		}
	}
	public static void main(String[] args) {
		System.out.println("Main method started");
		Sample sample=new Sample();
		sample.start();
	}
}

Output:

Main method started
2 4 6 8 10 

• On invoking start() on a thread, the thread is registered to the thread scheduler of JVM once JVM allocates a new stack it calls the run() method to do execution on the new stack.
• If we directly invoke the run() instead of start() the execution happens on the current stack which will not allow achieving parallel execution.