Autoboxing and Unboxing in Java – AutoboxingAutoboxing refers to the automatic conversion of a primitive type variable to its corresponding. Autoboxing in java was introduced in Java Autoboxing and unboxing is a convenient way to auto transform primitive data type to it’s corresponding java. Primitive variables in Java contain values (an integer, a double-precision floating point Auto Boxing also comes in handy when we are working with

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There are other good reasons, such as a “int” field in a database, which could be NULL as well. This article attempts to elaborate on autoboxing, auto-unboxing, and its allied ideas as applied to principle of Java programming. The technique of converting an expression of primitive type as an expression of a corresponding reference type is called boxing conversion. While running the below code, NullPointerException NPE can be thrown and it is not quite obvious from the code if you are not aware of autoboxing.

Autoboxing and Its Pitfalls

Performance is likely the reason for having primitive types. References are typically implemented as pointers or something very similar to pointers in many languages. What is your company size? The primary advantage of a class is that it encompasses not only the data as its property but also methods that enhance or modify the behaviour uatoboxing the property which may autiboxing designated and exposed as the functionality of the class. Similarly, other data types have their specific size and range of stored values.


Anything else or other than the preceding primitives are a non-primitive or composite type. So without boxing to Object one would need to compile classes for every occurrence of a parameter type. For example, an int can store autlboxing integer numeric values that are only within a certain range of bit.

The eight data types and their values.

This idea can be exploited to the advantage of the programmer in a way where the seemingly simple looking primitive types are geared up with additional features. If you have been thinking about what if the expression was this instead:.

AutoBoxing is the process for which a primitive type is automatically aautoboxing in the equivalent wrapper whenever such an object is needed.

Today This Week All-Time. Rest assured the principles behind it are intriguing and worth knowing. Unexpected Behavior Confused Equals Autoboxing has brought with itself a lot of things that just are not obvious to a programmer.

Now, this a lossy conversion.

Autoboxing and Unboxing in Java –

Autoboxing is the automatic conversion that the Java compiler makes between the primitive types and their corresponding object wrapper classes. Learn more about Kotlin. For example, the String data type we use in Java is actually a class which is a collection of char data types.

Because primitive types are the building blocks of Java code, there must be some convenient conversion techniques between primitives and wrappers. Published at DZone with permission of T Tak.


This property of class variables makes the references they contain interchangeable to an extent. An int in Java cannot be null ; an Integer reference can. The primitive non-object types have there justification in efficiency. Join the DZone community and get the full member experience. If the conversion goes the other way, this is called unboxing.

Revisiting Java SE 5 Features! Converting a primitive value an intfor example into an object of the corresponding wrapper class Integer is called autoboxing. The version for Object would handle all child classes.

An Integer is not javva substitute for an int; autoboxing and unboxing blur the distinction between primitive types and reference types, but they do not eliminate it. Guess what, there actually is.

Why do we use autoboxing and unboxing in Java? – Stack Overflow

Because these values may have different lengthsthe variables containing them may also have different lengths consider float versus double. Therefore, every variable and expression have a type that must be known before compilation. Let’s see down the line. Primitive variables aren’t interchangeable in the same qutoboxing, neither with each other, nor with Object.