---
title: "How can I create a memory leak in Java?"  
description: "How can I create a memory leak in Java?"  
author: "Utpal Vishwas"  
published: 2023-07-21  
updated: 2023-07-22  
canonical: https://www.mindstick.com/forum/159215/how-can-i-create-a-memory-leak-in-java  
category: "java"  
tags: ["java", "memory", "memory management"]  
reading_time: 4 minutes  

---

# How can I create a memory leak in Java?

How can I create a [memory leak](https://www.mindstick.com/forum/159533/when-a-memory-leak-might-occur-in-c-plus-plus-and-how-can-avoid-it) in [Java](https://www.mindstick.com/articles/12214/web-development-company-in-india-laid-on-the-foundation-of-concrete-java-programming)?

## Replies

### Reply by Aryan Kumar

There are a few ways to create a [memory](https://www.mindstick.com/blog/300050/what-causes-sudden-memory-loss) leak in Java.

- **Creating a circular reference.** A circular reference occurs when two objects refer to each other. This can cause the garbage collector to be unable to deallocate the memory that is allocated to the objects.

Here is an example of how to create a circular reference:

```plaintext
class A {

  private B b;

  public A(B b) {
    this.b = b;
  }

  public B getB() {
    return b;
  }
}

class B {

  private A a;

  public B(A a) {
    this.a = a;
  }

  public A getA() {
    return a;
  }
}

public class Main {

  public static void main(String[] args) {
    A a = new A(new B(a));
  }
}
```

In the code above, the `A` object and the `B` object refer to each other. This creates a circular reference, which can cause the garbage collector to be unable to deallocate the memory that is allocated to the objects.

- **Not releasing objects that are no longer needed.** Another way to create a memory leak is to not release objects that are no longer needed. This can happen if you are using a `while` loop to iterate over a collection of objects, and you do not release the objects after you have finished iterating over them.

Here is an example of how to create a memory leak by not releasing objects that are no longer needed:

```plaintext
class MyClass {

  public static void main(String[] args) {
    List<Object> objects = new ArrayList<>();
    for (int i = 0; i < 10000; i++) {
      objects.add(new Object());
    }

    while (true) {
      for (Object object : objects) {
        // Do something with the object
      }
    }
  }
}
```

In the code above, the `while` loop will continue to iterate over the collection of objects, even though the objects are no longer needed. This will eventually cause the Java Virtual Machine (JVM) to run out of memory.

- **Using objects that are allocated on the heap in a thread-unsafe manner.** Objects that are allocated on the heap are shared by all threads in the JVM. If you use these objects in a thread-unsafe manner, it can lead to memory leaks.

Here is an example of how to create a memory leak by using objects that are allocated on the heap in a thread-unsafe manner:

```plaintext
class MyClass {

  private static Object object = new Object();

  public static void main(String[] args) {

    Thread thread1 = new Thread(new Runnable() {
      @Override
      public void run() {
        synchronized (object) {
          // Do something with the object
        }
      }
    });

    Thread thread2 = new Thread(new Runnable() {
      @Override
      public void run() {
        synchronized (object) {
          // Do something with the object
        }
      }
    });

    thread1.start();
    thread2.start();
  }
}
```

In the code above, the `object` variable is allocated on the heap. The `main()` method creates two threads, and each thread tries to acquire a lock on the `object` variable. If the threads acquire the lock at the same time, it can cause a deadlock. This deadlock can prevent the garbage collector from collecting the `object` variable, which can lead to a memory leak.

Here are some ways to prevent memory leaks in Java:

**Avoid creating circular references.** Circular references can be prevented by ensuring that objects do not refer to each other. This can be done by using the `weakReference()` method to create a weak reference to an object. Weak references are not strongly held by the garbage collector, which means that the garbage collector can deallocate the memory that is allocated to the object if it is no longer needed.

**Release objects that are no longer needed.** Objects that are no longer needed should be released by calling the `finalize()` method on the object. The `finalize()` method is called by the garbage collector before it deallocates the memory that is allocated to the object.

**Use thread-safe objects.** Objects that are allocated on the heap should be used in a thread-safe manner.


---

Original Source: https://www.mindstick.com/forum/159215/how-can-i-create-a-memory-leak-in-java

Copyright © MindStick Software Pvt. Ltd. This Markdown version is provided for developers, AI systems, and offline reading.