Multithreading is a feature in Java that allows multiple threads of execution to run concurrently within a single program. In other words, it is the ability of the Java Virtual Machine (JVM) to execute multiple threads simultaneously. Each thread is a lightweight, independent unit of execution that runs within the context of a single program. Each thread has its own call stack and can execute code independently of other threads.
Multithreading is used in Java to improve the performance and responsiveness of programs, especially in applications that involve heavy computation or I/O operations. For example, a web server can use multithreading to process multiple requests simultaneously without blocking the user interface. Similarly, a video game can use multithreading to update the graphics and user input at the same time.
In Java, there are two ways to create threads: by extending the Thread class or by implementing the Runnable interface. To create a thread by extending the Thread class, you need to create a subclass of Thread and override the run() method. To create a thread by implementing the Runnable interface, you need to create a class that implements the Runnable interface and override the run() method.
Thread synchronization is an important aspect of multithreading in Java, as it helps avoid data corruption or race conditions when multiple threads share the same data. Java provides several mechanisms for thread synchronization, including the synchronized keyword, locks, and semaphores. The synchronized keyword is used to synchronize access to a block of code or a method, while locks and semaphores provide more fine-grained control over thread synchronization.
Overall, multithreading is a powerful feature in Java that can improve the performance and responsiveness of programs. However, it is important to use it carefully and properly synchronize access to shared data to avoid problems such as data corruption or race conditions.
