Skip to content

multithread

Directory actions

More options

Directory actions

More options

Latest commit

 

History

History

multithread

Folders and files

NameName
Last commit message
Last commit date

parent directory

..
PrintTask.java
PrintTask.java
 
 
TestMultiThread.java
TestMultiThread.java
 
 
readme.md
readme.md
 
 

readme.md

☕ Java Lesson – Executor in Multithreading (Thread Pool)

Is lesson me hum seekhenge:

  • Executor ka role multithreading me
  • Thread Pool kya hota hai
  • Multiple threads ka use
  • Practical examples
  • Performance benefits

1️⃣ Executor in Multithreading Kya Hota Hai?

Executor ka use hota hai:

multiple threads ko efficiently manage karne ke liye

Instead of:

har baar new Thread create karna ❌

Use:

thread pool reuse ✔

2️⃣ Thread Pool Kya Hota Hai?

Thread Pool:

threads ka ek group hota hai jo tasks execute karta hai

✔ thread reuse hota hai
✔ performance better hoti hai

3️⃣ Fixed Thread Pool (Most Common)

ExecutorService executor = Executors.newFixedThreadPool(3);

✔ max 3 threads ek time par run honge

4️⃣ Multi-thread Execution Example

import java.util.concurrent.*;

class Test {

    public static void main(String[] args){

        ExecutorService executor = Executors.newFixedThreadPool(3);

        for(int i = 1; i <= 6; i++){

            int taskId = i;

            executor.execute(() -> {
                System.out.println("Task " + taskId +
                    " running on " + Thread.currentThread().getName());
            });
        }

        executor.shutdown();
    }
}

5️⃣ Output Behavior

3 threads ek time par kaam karenge
baaki tasks queue me wait karenge

6️⃣ Thread Pool Working

Tasks → Queue → Available Thread → Execution

7️⃣ Cached Thread Pool

ExecutorService executor = Executors.newCachedThreadPool();

✔ dynamic threads create karta hai
✔ fast but risky (too many threads)

8️⃣ Scheduled Thread Pool

ExecutorService executor = Executors.newScheduledThreadPool(2);

✔ delay ya periodic tasks ke liye

9️⃣ Example – Delay Execution

ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);

executor.schedule(() -> {
    System.out.println("Task after 2 sec");
}, 2, TimeUnit.SECONDS);

🔟 Runnable Task Example

Runnable task = () -> {
    System.out.println("Task running");
};

executor.execute(task);

1️⃣1️⃣ Callable + Future (Multithread)

Callable<Integer> task = () -> {
    return 100;
};

Future<Integer> result = executor.submit(task);

System.out.println(result.get());

1️⃣2️⃣ Advantages of Executor in Multithreading

✔ thread reuse
✔ better CPU utilization
✔ scalable system
✔ less memory overhead

1️⃣3️⃣ Important Points

✔ Thread creation expensive hota hai
✔ Executor reuse karta hai threads
✔ always shutdown executor

1️⃣4️⃣ Real-Life Analogy

Restaurant kitchen:
Chefs (threads) fix hain
Orders (tasks) queue me aate hain

🎯 Interview Questions

  1. Thread pool kya hota hai?
  2. Fixed thread pool ka use kya hai?
  3. Executor vs Thread difference?
  4. Cached thread pool kab use karte hain?

🧾 Lesson Summary

Is lesson me humne seekha:

✔ Executor in multithreading
✔ Thread pool concept
✔ Fixed, cached, scheduled pools
✔ Practical execution

Executor multithreading me efficient, scalable aur optimized execution provide karta hai.