Java Multithreading

What is multithreading in Java?

Multithreading is a feature of Java that allows two or more portions of a program to run concurrently, maximizing CPU utilization. Each component of such a program is referred to as a thread. Thus, threads are lightweight processes within processes.

Benefits of Multithreading in Java

• Multithreading in Java increases performance and reliability.
• Multithreading in Java significantly reduces execution time.
• Multithreading in Java provides a seamless and hassle-free GUI response.
• The software maintenance costs are reduced.
• The CPU and other processing resources are properly used.

Disadvantages of Java Multithreading

• Multithreading in Java complicates code debugging.
• In Java, the likelihood of a process execution deadlock increases when several threads are used.
• In worst-case scenarios, the result may be unpredictable.
• Complications may arise while code is being transferred.

Process vs Threads

• Threads are contained within processes, whereas processes are standalone.
• Threads are lightweight, whereas processes are heavy.
• Threads lack separate memory and resources, whereas processes do.
• Threads require synchronization, whereas processes do not.
• Threads share address space for direct communication, while processes communicate via inter-process communication

What is the Main Thread in Java?

When a Java program starts, one thread runs instantly. This is commonly referred to as the program's main thread because it is performed when the program starts.

Properties of Main Thread

• The main thread creates child threads.
• The main thread usually finishes last, executing shutdown operations.

Creating a new thread in Java

To create a new thread in Java, first instantiate a class that extends the Thread class or implements the Runnable interface, and then call the start() method to start the new thread's execution.

Thread with Loop in java

In Java, a thread containing a loop is created by enclosing a loop within the run() method of a Thread subclass or a Runnable implementation and then beginning the thread to execute the loop concurrently.

Thread Lifecycle

In Java, a thread can be in any of the following states. The states are:

• New
• Active
• Blocked / Waiting
• Timed Waiting
• Terminated