What is Java Thread Life Cycle?
Tags: java, javascript, webdev, coding
Published: 2023-04-29 10:58:55

Java is a multi-threaded language, which means it can process numerous independent threads of code at once. A thread is a separate line of code that may run at any given time. From its inception to its eventual death, a Java thread goes through a series of phases defined by the Java Thread Life Cycle. This article will walk you through each step of the Java Thread Life Cycle.

A [java online course](https://www.niit.com/india/java-full-stack-developer-program?utm_source=off-page-seo&utm_medium=javaDP-submission&utm_campaign=guest-blogging) will give you more learning flexibility.

## The Java Thread Life Cycle

The Java Thread Life Cycle consists of the following states:

**1. New**
When a thread is established but has not yet begun executing, it enters the new state. At this point, the thread is not regarded to be operating and has not been given access to any system resources.

**2. Runnable**
The runnable state is reached by a thread when it is ready to execute but has not yet been given the green light to do so by the operating system. In this condition, the thread is awaiting the assignment of a processor. A thread may go from the new or blocked state to the runnable state.

**3. Blocked**
When a thread reaches the blocked state, it is waiting for the release of a monitor lock. It occurs when one thread tries to use a synchronised section of code that is already being used by another thread. The thread is now in a wait state, waiting for the lock to be released before it may return to the runnable state.

**4. Waiting**
When a thread is waiting for another thread to do some work, it is said to be in the waiting state. The thread is now waiting forever for either another thread to notify it or for the timeout to expire.

**5.Timed Waiting**
When a thread has to wait for a certain amount of time, it transitions into the timed waiting state. The thread will remain in this waiting state until either the timeout period ends or it receives a notification from another thread.

**6.Terminated**
When a thread has finished its execution or thrown an exception that was not captured, it transitions to the terminated state. It is not possible to restart a thread after it has entered the terminated state.

**7.Thread Transitions**
There are several methods in which a thread might change from one state to another. Among them are:

**8.Starting a Thread**
The start() function initiates a new thread. This changes the thread's status to one where it may be executed.

**9.Waiting for a Monitor**
The blocked state is entered by a thread while it is waiting for the unlocking of a monitor lock.

**10. Sleeping**
By using the sleep() function, a thread may enter a timed waiting state.

**11. Waiting for a Condition** 
Using wait() or wait(long timeout), a thread may enter the waiting or timed waiting state.

**12. Resuming a Thread** 
If a thread is in the waiting or timed waiting state, it may return to the runnable state by using the notify() or notifyAll() operations.

**13. Terminating a Thread**
The terminated state is reached when a thread has finished executing or when an exception has been thrown but not caught.

## Best Practices for Working with Threads

There are several guidelines that developers should adhere to in order to make the most of threads. Among them are:

**1. Avoiding Deadlocks** 
When two or more threads are waiting on each other to free a lock, a deadlock occurs. Programmers should always release locks on time to prevent deadlocks.

**2. Using Thread Pools**
A program's performance may suffer if too many threads are created, although using thread pools may assist alleviate this problem.

**3. Avoiding Busy Waiting**
When a thread is not waiting for a message but instead constantly checking a condition in a loop, this is known as busy waiting. This is not recommended since it might lead to performance concerns.

**4. Synchronizing Access to Shared Resources**
It is vital to synchronise access when different threads use the same variables or data structures to avoid data inconsistencies and race scenarios. The use of synchronised blocks or approaches may accomplish this.

**5. Minimizing the Use of Thread.sleep()**
Using Thread.sleep() may result in threads blocking for a long time, which can degrade performance. Alternative techniques, such as wait() and notify(), are advised for managing threads.

**6. Using Thread-safe Data Structures**
When many threads are trying to access the same data at the same time, race situations may arise; thread-safe data structures like ConcurrentHashMap and ConcurrentLinkedQueue can assist alleviate this problem.


## Conclusion
In conclusion, a Java thread goes through a series of phases known as its "life cycle," which are defined by Java. When developing multi-threaded applications, knowledge of thread states and transitions is crucial. Best practises for dealing with threads help ensure applications are scalable, efficient, and free of frequent problems like deadlocks and race situations.
A [java development course](https://www.niit.com/india/java-full-stack-developer-program?utm_source=off-page-seo&utm_medium=javaDP-submission&utm_campaign=guest-blogging) will give you better insights into this topic.