Thread Life Cycle - 1.1.3 | 1. Multithreading and Concurrency | Advance Programming In Java
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Interactive Audio Lesson

Listen to a student-teacher conversation explaining the topic in a relatable way.

Thread States Overview

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Teacher
Teacher

Today, we will discuss the thread life cycle in Java. Can anyone tell me what they think happens when a thread is created?

Student 1
Student 1

I think it goes into a kind of waiting state until it gets started.

Teacher
Teacher

Great observation! When a thread is created, it is in the 'New' state. This means it has been instantiated but not started yet. Now, what happens once we initiate it?

Student 2
Student 2

It becomes Runnable, right?

Teacher
Teacher

Exactly! The thread moves to the 'Runnable' state where it waits for CPU availability. It’s important to remember that 'Runnable' means it is ready to run, but not necessarily running yet. Let's remember this with the acronym 'NRR' for New, Runnable, Running.

Running and Blocked States

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Teacher
Teacher

Now, let's delve deeper. What does it mean when a thread is in the 'Running' state?

Student 3
Student 3

It means the thread is currently executing its task.

Teacher
Teacher

Correct! The 'Running' state indicates that the thread is performing its task actively. But what can cause a thread to enter the 'Blocked/Waiting' state?

Student 4
Student 4

It happens when it's waiting for a monitor lock, like when other threads are holding resources.

Teacher
Teacher

That's a perfect explanation! We can recall this concept with the phrase 'Locking leads to Blocking.' Remember to always check if resources are available before a thread tries to execute.

Termination of Threads

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Teacher
Teacher

Finally, let's talk about the 'Terminated' state. Can anyone tell me what might cause a thread to reach this status?

Student 1
Student 1

It could finish its task or be stopped by another thread.

Teacher
Teacher

Exactly! Once a thread finishes executing its run method, it transitions to the 'Terminated' state. To remember the states more easily, think of the phrase 'Born, Ready, Busy, Waiting, Goodbye.'

Introduction & Overview

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Quick Overview

The thread life cycle in Java describes the various states a thread can be in during its execution.

Standard

In the thread life cycle, a Java thread can exist in one of five states: New, Runnable, Running, Blocked/Waiting, and Terminated. Understanding these states is crucial for managing thread behavior effectively in a multi-threaded application.

Detailed

Thread Life Cycle

In Java, a thread can exist in one of the following states, illustrating its status during execution:

  1. New: When a thread is created but not yet started. It is essentially an object of the Thread class that has not begun its activity.
  2. Runnable: The thread is eligible to run and is waiting for CPU availability. This means the thread can be in a state of execution but isn't guaranteed to be actively running.
  3. Running: The thread is actively executing its task.
  4. Blocked/Waiting: Indicates that the thread is not able to proceed because it is waiting for a monitor lock (to enter a synchronized block or method) or is waiting for a signal (like wait()) from another thread.
  5. Terminated: The thread has completed its execution, either by finishing its work or by being stopped forcibly.

Understanding these states is essential for managing thread behavior effectively, as it impacts synchronization and resource accessibility in concurrent applications.

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Audio Book

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Thread States Overview

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A thread in Java can be in one of the following states:
1. New – Created but not yet started.
2. Runnable – Eligible to run, waiting for CPU.
3. Running – Actively executing.
4. Blocked/Waiting – Waiting for a monitor lock or a signal.
5. Terminated – Execution completed or stopped.

Detailed Explanation

In Java, a thread can exist in five different states throughout its life cycle.
1. New: This is the initial state when a thread is created but hasn't started executing yet. It is only in memory, and its method start() needs to be called to transition it.
2. Runnable: Once the thread is eligible to run but is waiting for the CPU, it is in this state. It can transition to the Running state when the CPU scheduler allocates CPU time to it.
3. Running: This is the state where the thread is actively executing its code. This state is where the thread performs its intended functions.
4. Blocked/Waiting: A thread enters this state when it is waiting for a resource (like a lock) or a signal to continue its execution. This can happen if another thread holds the resource it needs.
5. Terminated: Once a thread completes its execution or is stopped, it enters the Terminated state. At this point, the thread has released all its resources.

Examples & Analogies

Think of a thread's life cycle like a worker in an office.
- The 'New' state is similar to when a new employee joins the company but hasn’t started working yet.
- In the 'Runnable' state, the worker is ready and waiting for their turn to work on a project, just like waiting in a line.
- The 'Running' state is when the employee is actively working on their tasks and completing them.
- In the 'Blocked/Waiting' state, the worker might be waiting for a colleague to provide them with information or resources to complete their work. Finally, when they finish all tasks or leave the company, they enter the 'Terminated' state.

Definitions & Key Concepts

Learn essential terms and foundational ideas that form the basis of the topic.

Key Concepts

  • New: Indicates the initial state of a thread.

  • Runnable: Ready to run but not yet executing.

  • Running: Actively executing the thread’s task.

  • Blocked/Waiting: Inability to proceed due to waiting for locks or signals.

  • Terminated: Indicates thread completion.

Examples & Real-Life Applications

See how the concepts apply in real-world scenarios to understand their practical implications.

Examples

  • A newly created thread is in the 'New' state until the start method is called.

  • A thread becomes 'Runnable' when it is eligible for CPU time after starting.

  • Once a thread's run method completes, it transitions to the 'Terminated' state.

Memory Aids

Use mnemonics, acronyms, or visual cues to help remember key information more easily.

🎡 Rhymes Time

  • When the thread's in view, it's just 'New', then it 'Runs' for you, and then 'Blocks' too, finally say 'Adieu.'

πŸ“– Fascinating Stories

  • Imagine a race: A runner is born ('New'), waits his turn to run ('Runnable'), sprints on the track ('Running'), pauses to catch his breath ('Blocked'), and finally finishes the race ('Terminated').

🧠 Other Memory Gems

  • Remember 'N-R-R-B-T': New, Ready, Running, Blocked, Terminated.

🎯 Super Acronyms

'RBLT' - Running, Blocked, and then Life ends at Terminated for threads.

Flash Cards

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Glossary of Terms

Review the Definitions for terms.

  • Term: New

    Definition:

    State of a thread that has been created but not yet started.

  • Term: Runnable

    Definition:

    State of a thread that is ready to run and waiting for CPU time.

  • Term: Running

    Definition:

    State of a thread that is currently executing its task.

  • Term: Blocked/Waiting

    Definition:

    State of a thread that is unable to proceed until it acquires a monitor lock or receives a signal.

  • Term: Terminated

    Definition:

    State of a thread that has completed its execution.