Shulou(Shulou.com)06/02 Report--

What is the meaning of memory leak? aiming at this problem, this article introduces the corresponding analysis and answer in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible way.

1. What is a memory leak?

Definition of memory leak: objects are no longer used by the application, but the garbage collector cannot remove them because they are being referenced.

To understand this definition, we need to understand the state of the object in memory, and the following figure shows what is unused and which is not referenced.

You can see referenced objects and unreferenced objects from the figure. Objects that are not referenced will be reclaimed by the garbage collector, while referenced objects will not be recycled. An object that is not referenced is naturally unused because no other object references it. However, unused objects are not necessarily unreferenced, some of which are referenced. This is the cause of the memory leak.

two。 Why is there a memory leak?

Let's take a look at the following example to see why memory leaks occur. In the following example, object A references object B. The life cycle (t1-t4) of An is much longer than that of B (t2-t3). When B is no longer used in the application, A still holds a reference to it. In this way, the garbage collector cannot remove B from memory. This may lead to out-of-memory problems, because if A does the same thing for more objects, there will be a lot of objects in memory that cannot be recycled, which will consume a lot of memory space.

It is also possible that B holds a large number of references to other objects, and these objects referenced by B cannot be recycled. All these unused objects will consume valuable memory space.

3. How do I stop memory leaks?

Here are some quick hands-on tips to prevent memory leaks.

Notice the collection classes, such as HashMap,ArrayList, and so on. Because they are places where memory leaks often occur. When they are declared static, their life cycle is as long as the life cycle of the application.

Note that event listeners and callbacks occur if a listener is registered but is not logged out when the class is no longer in use.

"if a class manages its own memory, programmers should be wary of memory leaks." [1] many times when the member variable of an object points to another object, it needs to be set to null when it is no longer in use.

So much for the answer to the question about what memory leak means. I hope the above content can be of some help to you. If you still have a lot of doubts to solve, you can follow the industry information channel to learn more about it.

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