Multithreading Introduction

Lecture 92:-  Multithreading Introduction

Multithreading is a fundamental concept in computer programming that allows a single process to execute multiple threads of execution concurrently. A thread is the smallest unit of execution within a process, and multithreading enables a program to perform multiple tasks simultaneously, thereby maximizing CPU utilization and improving the overall performance of the application.

In Java, multithreading is an integral part of the language and is supported through the java.lang.Thread class and the java.lang.Runnable interface. Java provides a high-level abstraction for creating and managing threads, making it easier for developers to work with multithreaded applications.

Key concepts and terminology related to multithreading in Java include:

1. Thread:
   • A thread is an independent path of execution within a process.
   • It represents a sequential flow of control, and each thread has its own program counter, register set, and stack.
   • Multithreading allows multiple threads to execute concurrently within the same program.
2. Process vs. Thread:
   • A process is an independent unit of execution that has its own memory space and resources.
   • A process can contain multiple threads, and these threads share the same memory space and resources of the process.
3. Creating Threads:
   • In Java, you can create a thread by extending the Thread class and overriding the run method, or by implementing the Runnable interface and providing the run method's implementation.
   • Implementing the Runnable interface is often preferred because it allows better flexibility in class design and supports multiple inheritance.
4. Thread States:
   • Threads can exist in various states, such as "new," "runnable," "blocked," "waiting," "timed waiting," and "terminated."
   • The Thread class provides methods to transition between these states and to control the execution of threads.
5. Thread Synchronization:
   • When multiple threads access shared resources, there is a possibility of data inconsistency and conflicts.
   • Thread synchronization mechanisms, such as synchronized blocks and locks, are used to prevent race conditions and ensure data consistency.
6. Thread Priorities:
   • Threads can be assigned priorities to influence their execution order.
   • Java provides thread priorities ranging from MIN_PRIORITY to MAX_PRIORITY, with NORM_PRIORITY being the default.
7. Thread Pooling:
   • Creating and destroying threads can be resource-intensive. Thread pooling is a technique where a pool of reusable threads is created and maintained, avoiding the overhead of thread creation.

Multithreading is used in various applications to improve responsiveness, scalability, and resource utilization. It is particularly beneficial for tasks that involve I/O operations, long-running computations, or parallel processing of data. However, multithreading also introduces challenges, such as thread safety and deadlocks, which must be carefully managed to ensure correct behavior and avoid potential issues.