Data Types in Java – Primitive and Non-Primitive Data Types Explained

In Java, data types play a crucial role in defining the kind of information that can be stored and manipulated. Primitive data types, such as integers, floating-point numbers, characters, and booleans, provide the foundation for representing simple values. On the other hand, non-primitive data types, like arrays, classes, and interfaces, enable the creation of more complex structures and allow for the organization and manipulation of larger sets of data. Understanding and effectively utilizing these data types is essential for developing robust and efficient Java programs. Let’s understand!!

A data type is a classification of data. It tells the compiler or interpreter how the programmer aims to use the variables or method. Data types are a crucial factor in all computer programming languages. The task of a programmer is to develop a workable program by assigning the right types of data to the right variables. Data types represent the type, nature, and set of operations for the value which they store. There are two data types of categories in Java: Primitive and Non-Primitive.

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What are Data Types in Java?

Data types in Java specify how memory stores the values of the variable. Each variable has a data type that decides the value the variable will hold. Moreover, Primitive Data Types are also used with functions to define their return type.

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Data Types in Java

Data types in Java are divided into 2 categories:

1. Primitive Data Types
2. Non-Primitive Data Types

Source: Crunchify

Primitive Data Types

Primitive data types specify the size and type of variable values. They are the building blocks of data manipulation and cannot be further divided into simpler data types.

Source: Crunchify

There are 8 Primitive data types in Java – Boolean, char, byte, int, short, long, float, and double.

For more information, Read Access Modifiers in Java.

Boolean type – Boolean

A boolean data type can store either True or False. They can be used to check whether two values are equal or not (basically in conditional statements to return True or False). Typically, programmers use it as a flag variable to track true or false conditions.

The default boolean value is False. Moreover, the boolean type’s size depends on the Java Virtual Machine. Therefore, it fluctuates on different platforms.

Example-

Output-

Character type – char

The char data type stores a single character. It stores lowercase and uppercase characters, which must be enclosed in single quotes. The char data type in Java supports Unicode characters and provides provision to multiple languages like English, French, German, etc. It takes memory space of 16 bits or 2 bytes. The values stored range between 0 to 65536.

Example:-

Output:

Integer type –

An integer type stores an integer number with no fractional or decimal places. Java has four integer types – byte, short, int, and long.

Byte

The byte is the smallest data type among all the integer data types. It is an 8-bit signed two’s complement integer. It stores whole numbers ranging from -128 to 127.

Syntax:

byte byteVariable;

Short

Short is a 16-bit signed two’s complement integer. It stores whole numbers with values ranging from -32768 to 32767. Its default value is 0.

Syntax:

short shortVariable;

Int

Int is a 32-bit signed two’s complement integer that stores integral values ranging from 2147483648 (-2^31) to 2147483647 (2^31 -1). Its default value is 0.

Syntax:

int intVariable;

Long 

long is a 64-bit signed two’s complement integer that stores values ranging from -9223372036854775808(-2^63) to 9223372036854775807(2^63 -1). It is used when we need a range of values more than those provided by int. Its default value is 0L. This data type ends with ‘L’ or ‘l’.

Syntax:

long longVariable;

Example:

Output:

Float type –

Floating-point is used for expressions involving fractional precision. It has two types: float and double.

Float

It is a floating-point data type that stores the values, including their decimal precision. It is not used for precise data such as currency or research data.

A Float value:

• is a single-precision 32-bit or 4 bytes IEEE 754 floating-point
• can have a 7-digit decimal precision
• ends with an ‘f’ or ‘F’
• default value = 0.0f
• stores fractional numbers ranging from 3.4e-038 to 3.4e+038

Syntax:

float floatVariable;

Double 

The double data type is similar to float. The difference between the two is that is double twice the float in the case of decimal precision. It is used for decimal values just like float and should not be used for precise values.

A double value:

• is a double-precision 64-bit or 8 bytes IEEE 754 floating-point
• can have a 15-digit decimal precision
• default value = 0.0d
• stores fractional numbers ranging from 1.7e-308 to 1.7e+308

Syntax:

double doubleVariable;

Example:

Output:

Primitive Data Types Table – Default Value, Size, and Range

Non-Primitive Data Types

Non-primitive data types or reference data types refer to instances or objects. They cannot store the value of a variable directly in memory. They store a memory address of the variable. Unlike primitive data types we define by Java, non-primitive data types are user-defined. Programmers create them and can be assigned with null. All non-primitive data types are of equal size.

Source: Crunchify

Array

An array holds elements of the same type. It is an object in Java, and the array name (used for declaration) is a reference value that carries the base address of the continuous location of elements of an array.

Example:

int Array_Name = new int[7];

For more insights about Arrays in Java, Read: Implementing Arrays in Java

String

The String data type stores a sequence or array of characters. A string is a non-primitive data type, but it is predefined in Java. String literals are enclosed in double quotes.

Class

A class is a user-defined data type from which objects are created. It describes the set of properties or methods common to all objects of the same type. It contains fields and methods that represent the behaviour of an object. A class gets invoked by the creation of the respective object.

There are two types of classes: a blueprint and a template. For instance, the architectural diagram of a building is a class, and the building itself is an object created using the architectural diagram.

Example:

For more details, read: OOPs Concepts in Java

Interface

An interface is declared like a class. The key difference is that the interface contains abstract methods by default; they have nobody.

Example:

Also Read: Python Vs Java – Which One is Better to Learn?

Enum

An enum, similar to a class, has attributes and methods. However, unlike classes, enum constants are public, static, and final (unchangeable – cannot be overridden). Developers cannot use an enum to create objects, and it cannot extend other classes. But, the enum can implement interfaces.

//declaration of an enum
enum Level {
  LOW,
  MEDIUM,
  HIGH
}

Conclusion

Data types are the basis of programming languages. It is essential to know about Java data types before moving to the advanced concepts of Java. Understanding data types will help you create a simple program or develop any application or software.

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