Everything To Know About Memory Allocation in Java: How does it Work?

Everything To Know About Memory Allocation in Java: How does it Work?

Memory allocation in Java is a process that involves freeing up space for different objects. The language Java has its in-built credibility of managing its memory. Now, an innovative autonomous technique called “garbage collector” is used by Java. And it never encourages the implementation of memory management logic in its program.

Why do You need to Learn About Memory Management in Java?

It is a known fact that Java manages its memory. Here, the garbage collection technique ensures the freeing up of space in the memory.  In this part, a question arises if there is already a technique available that works independently in managing memory, then what will be the functional area of a programmer?

Well, here you need to understand that everything related to managing memory cannot be done by a programmer. The programmer can overlook the challenge of object destruction but the programming team might have to deal with Java Virtual Machine (JVM) often if they have limited knowledge about how garbage collector functions.

What is the basic structure of Memory in Java?

Before you dive deep into understanding memory allocation in Java, take into consideration the basic memory structure in Java. When you talk about memory in a programming language, it specifically means the instructions, stored values, or data. The memory section in Java is divided into two sections. One is Heap memory and the other one is Stack memory. Let’s understand these two types of memory structures in Java.

Stack memory is RAM or physical space. It is divided into many Java objects which are required during a website’s running time. Before the execution of a thread, the Stack memory is created. It further contains method-specific and short-lived values. The USP of Stack memory is, it creates a completely new block when there is any method is invoked.  When this method dissolves, the block becomes free in that Stack memory.

Heap memory is the area where all kinds of Java objects reside. Heap memory is created by Java Virtual Machine. So, the Java program uses Heap memory whenever the application is running. To add more to it, Heap memory is further divided into many generations. It helps the Java programs in storing new objects. Heap memory has generations such as Young and Old.

The Young generation has a defined timeline to store new objects. Whenever the timeline finishes, the new objects are shifted to the old generation. Apart from the Young and old generations, there is one more generation which is called as Permanent generation. Here the metadata and other application methods are stored.

Some Key Features of Stack Memory

To understand Stack memory in detail, let’s consider some of the key features of Stack memory.

• Variables of Java object exist inside blocks and stays there until the methods are working fine.
• When the method finishes all execution, the blocks are allocated and deallocated.
• The access to Stack memory functions fast and often it is compared to Heap memory.
• All threads which are generated inside the memory is safe and it is operated on their own Stack memory.

Top Methods in the Stack Class

Object pop: Returns and removes all top elements of the stack.

Object push: This is an object element that pushes the element on the top of the Stack memory.

Object peek: Pushes this element to the top of the stack, it never removes it.

Int Search: It determines the presence of the object inside the stack.

Some Key Features of Heap Memory

• The OutOfMemory error message is pushed through when Heap memory becomes full.
• Stack memory is more accessible than Heap Memory.
• Heap memory is much more spacious and efficient in keeping the object elements.
• As almost all objects share the space of Heap memory, it is not thread-safe.

Basic Differences Between Heap and Stack Memory

There are differences between heap and stack memory in terms of flexibility, ordering, application, efficiency, and many more. Hire Java developers to make your website development smoother. Now, let’s take a look at the disparities between stack and heap memories.

Ordering: Being a dynamic memory allocation, Heap memory never follows an order. Also, Heap memory does not have any such fixed pattern. On the other hand, Stack memory follows LIFO order.

Application: For applications, Heap memory stores Java Runtime Environment Classes and objects. However, Stack memory restores objects which have a short life. These objects are like methods and variables.

Flexibility: Heap memory is flexible in comparison to Stack memory because it can manage and alter allocated memory.

Efficiency: Heap memory has slower allocation and access in comparison to Stack.

Implementation: The implementation of Heap memory is easier than the stack.

Thread-safety: Heap memory is not at all thread-safe, therefore the Java developers require proper synchronization of the code. Stack memory, on the other hand, is thread-safe and all the threads have their own stack.

Wrapping Up

Java allocates memory using the heap and the stack. This article taught us how they operate and when to apply them to improve Java programs. See this article for more information on memory allocation in Java.

FAQs

Q1. What are the types of memory allocation in Java?

Ans. Well, there are nearly 5 kinds of memories in Java. These include:

Method Area

Stack Memory

PC Registers

Heap Memory

Native Area

Q2. What is the place where the memory is allocated?

Ans. In Java language, you need to write new() for allocating memory to an object. Therefore, the object always gets an allocation of memory in the Heap area.

Q3. How many memory allocations are there in JVM?

Ans. There is a physical memory availability for each JVM of 4096 MB;0.5 GB is for JVM allocation. This is nothing but a simplified calculation that includes 16GB memory that can run on 3 JVMs.