![class MultithreadingDemo extends Thread{
public void run()
{
System.out.println("My thread is in running state.");
}
public static void main(String args[])
{
MultithreadingDemo obj=new MultithreadingDemo();
obj.start();
} }
Output:
My thread is in running state.
Example program](https://image.slidesharecdn.com/threadingconcepts-190201152723/85/Threading-concepts-11-320.jpg)
![class MultithreadingDemo implements Runnable
{
public void run()
{
System.out.println("My thread is in running state.");
}
public static void main(String args[])
{
MultithreadingDemo obj=new MultithreadingDemo();
Thread tobj=new Thread(obj);
tobj.start();
} }
Output:
My thread is in running state.
Runnable interface-example program](https://image.slidesharecdn.com/threadingconcepts-190201152723/85/Threading-concepts-29-320.jpg)
Threading concepts
- 2. Light weight process Smallest unit of processing Share some memory area of the process Thread is executed inside the process Executing multi threads simultaneously WHAT IS THREAD
- 3. WHAT IS MULTITHREADING Multi processing Multi threading Separate memory space Share same memory Heavy weight Light weight process Time and cost is more Less cost and time
- 4. Threads are light weight process Because they share same memory space for child threads too. whereas process , do not allocate same memory space. Interthread communication is in expensive Context switching of threads are in expensive Process inside the interthread and context sensitive is costly Advantages of threads
- 5. Threads are implemented in the form of objects that contain a method is called run() method is the heart and soul of any thread public void run() { ………. (statement for implementing thread) ………. } Creating threads
- 6. The run() method should be invoked by an object of the concerned thread. This can be achieved by creating the thread the initiating it with help of another thread method called start(). Following two ways By creating a thread class: A class that extends thread class and override its run() method with the code required method Creating threads-con’d
- 7. By converting a class to a thread: Define a class that implements Runnable interface. The Runnable interface has only one method , run() that is to be defined in the method the code to be executed by the thread Creating threads-con’d
- 8. Declare the class as extending the thread class Implement the run() method Create a thread object and call the start() method to initiate the thread execution Declaring the class the thread class can be extended as follows Class MyThread extends Thread { …………. …………. …………. } Extending the thread class
- 9. Implementing the run() method: The run() method has been inherited by the Mythread. This method in order to implement the code to be executed by our thread. The basic implementation of run() like public void run() { ……… ……… ……… } Extending the thread class
- 10. Starting new thread: to actually create and run an instance of our thread class MyThread aThread = new MyThread(); aThread.start(); New objects of class MyThread, the thread will be Newborn state. The start() method to move into the runnable state Extending the thread class
- 11. class MultithreadingDemo extends Thread{ public void run() { System.out.println("My thread is in running state."); } public static void main(String args[]) { MultithreadingDemo obj=new MultithreadingDemo(); obj.start(); } } Output: My thread is in running state. Example program
- 12. Life cycle
- 13. We create a thread object, the thread is born and is said to be in newborn state. The thread is not yet scheduled for running Following things Schedule it for running using start() method Kill it using stop() method Life cycle – New born state
- 14. The running state means that the thread is ready for execution and is waiting for the availability of the process The thread has joined the queue of threads they are waiting for execution The process of assigning time to thread is called a time slicing We can using the yield() method Life cycle – Runnable state
- 15. Running means the process has been time to the thread for execution Following situations 1. It has been suspended using suspend() method. A suspended thread can be revived by using the resume() method. 2. It has been made to sleep. We can a thread to sleep for a specified time period using the method sleep(time).where time is in milliseconds Life cycle –Running state
- 16. 3. It has been hold to wait until some event occurs. This is done using wait() method. The thread can be scheduled to run again for the notify() method. Running state-con’d
- 17. A thread is said to be blocked when it is prevented from entering into the runnable state and subsequently the running state. The thread is suspended, sleeping, or waiting in order to satisfy certain requirement. A blocked thread is “not runnable” but not dead it has access to run again. Life cycle-blocked state
- 18. A running thread ends its life when it has completed executing its run() method. It is natural death A thread can be killed as soon it is born , or while it is running ,or even when it is “not runnable” (blocked) condition. Life cycle-Dead state
- 19. It can be default running When a program begins , one thread begins running immediately Importance of main threads A thread from which other “child” thread can be created Must be the threads to finish execution Current Thread() returns reference to the current thread It is public and static in nature thread objects Main thread
- 20. getName – get in thread name getPriority – thread get priorities isAlive – check if a thread is still running Join – wait for a thread to terminated run – entry point for the thread sleep – suspend a thread for a period of time start() – start a thread by calling its run method Thread methods
- 21. The call to sleep() method is enclosed in a try block and followed by a catch block. This is necessary because the sleep() method throws an exception. if we fail to catch the exception, program will not compile. Syntax Catch(threadDeath e) { …….. …….. } Thread execptions
- 22. Catch(InterruptedException e) { ……….. ……….. } Catch(Illegal ArgumentException e) { ……….. ……….. } Catch(Exception e) { ……….. ……….. } Thread exceptions-con’d
- 23. thread scheduler assigns processor to a thread based on priority of thread. Whenever we create a thread in Java, it always has some priority assigned to it. Java is set the priority is using method is setpriority() method. ThreadName.setPriority(intNumber); The intNumber is an integer value Thread priority
- 24. public static int MIN_PRIORITY: This is minimum priority that a thread can have. Value for this is 1. public static int NORM_PRIORITY: This is default priority of a thread if do not explicitly define it. Value for this is 5 public static int MAX_PRIORITY: This is maximum priority of a thread. Value for this is 10. Priority-con’d
- 25. Capability to control the access of multiple threads to a shared resource Why? To prevent the interference of threads To prevent consistency problems. Understanding locks Every object has a lock or monitor. A thread needs to acquire lock before accessing objects Types Process ,Thread synchronization
- 26. Mutual extension Co-operation Keeps threads from interfering with one another while sharing data Synchronized method Synchronized block Static synchronization Inter-thread communication synchronized threads to communicate with each others Thread synchronization
- 27. We can create two ways Using the extended Thread class Implementing the Runnable interface The Runnable interface declares the run() Method that is required for implementing threads in programs. Runnable interface
- 28. Following steps Declare the class as implementing the Runnable interface. Implement the run() method. Create a thread by defining an object that is instantiated from “runnable” class as the target of the thread Call the thread start() method to run the thread. Runnable interface
- 29. class MultithreadingDemo implements Runnable { public void run() { System.out.println("My thread is in running state."); } public static void main(String args[]) { MultithreadingDemo obj=new MultithreadingDemo(); Thread tobj=new Thread(obj); tobj.start(); } } Output: My thread is in running state. Runnable interface-example program
- 30. Thank you