Thread execution in Java refers to the way that the Java Virtual machine (JVM) executes the thread or a small unit of a program. In Java, threads can be created in a number of ways, including extending the Thread class, implementing the Runnable interface, or using executor services.
start() method in Thread
The start() method is used to begin the execution of a thread. When the start() method is called on a thread, the thread’s run() method is called by the JVM. The run() method is where the code that will be executed by the thread should be placed.
sleep() method in Thread
The sleep() method can be used to pause the execution of a thread for a specified amount of time. This can be useful for implementing delays or pausing the execution of a thread for a certain period of time. The sleep() method can throw an InterruptedException, so it should be used within a try-catch block or the method containing the sleep() call should declare that it throws InterruptedException.
join() method in Thread
The join() method can be used to wait for a thread to complete its execution. When the join() method is called on a thread, the calling thread will block until the thread it is joining completes its execution.
One way to create a new thread in Java is by extending the Thread class and overriding the run() method. And another way to create a thread in Java is by implementing the Runnable interface and providing an implementation of the run() method. I’ve written another post on how to create a thread in Java. You can visit there for more detail on this topic.
The start(), run(), sleep(), and join() methods are all important for controlling the execution of threads in Java. The start() method begins the execution of a thread, the run() method contains the code that will be executed by the thread, the sleep() method can be used to pause the execution of a thread for a specified amount of time, and the join() method can be used to wait for a thread to complete its execution. These methods provide a powerful way to control the concurrent execution of multiple threads in a Java program. These methods also improve the performance and responsiveness of the Java program.