Autoboxing in Java: The Silent Performance For Your Android App

At LinqTV, we always try to use best practices to ensure your app performs well across various devices. And memory optimization is a demanding task on that front.

Generally, while talking about memory optimization, most of us tend to think about the bigger sides. Due to this, we often miss the small things that can add up to a big problem. Autoboxing is one such topic that is often missed when talking about performance issues.

Autoboxing is often considered a great language feature. But as you keep using it, you start realizing its negative impact on your app’s performance. You cannot even imagine how much of your app’s memory is consumed by a simple Autoboxing operation.

So, in order to ensure optimized app performance, it’s really crucial to understand Autoboxing and find ways to avoid its negative impact. We have tried to do the same in this blog. Let’s dive in!

In Java, autoboxing converts a primitive value into a wrapper class’s object. For example, an int data type can be converted to an integer.

Most of the time, autoboxing is an automatic conversion performed by the Java compiler if the primitive value is:

For any version of JDK till JDK 1.4, it requires repetitive conversion of the primitive data types into wrapper classes and vice-versa.

Take, for example, you want to create a List with Integers. To do so, you will have to explicitly wrap them as Integer and then again unwrap them to get the int value. It can be troublesome and time-consuming.

To ease things out, conversion from primitive types to corresponding wrapper objects and vice versa is done automatically since JDK 1.5. The process is called Autoboxing and Unboxing, respectively. When building dynamic web applications with Java web development services, efficiency becomes paramount.

Autoboxing is the conversion of a primitive type to its corresponding reference type, as shown in the diagram below.

Unboxing is the reverse of autoboxing. If refers to the conversion of a wrapper type object to its respective primitive value. For example, an Integer object can be converted to an int data type via unboxing.

The Java compiler will perform unboxing when a wrapper class object is:

The process of unboxing is described in the diagram given below:

As we saw above, during autoboxing, Java provides the corresponding wrapper classes that match the primitive types, and act as object wrappers. These classes perform the same functionalities as primitive data types but can be used with generic collections.

However, here’s the major catch – their size in memory is not the same! For example, an Integer object occupies 4 times more memory as a primitive int.

In the code example given below, the API call is adding a primitive int value but the collection API takes an Integer object. This assignment will perform an Autoboxing operation from int to Integer object.

Here only a single call is taking place. So, in this case, it may not matter much.

But, if you are using similar operat