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Data types in Java

Data types in Java

Data types mainly represent the different sizes and values that can be stored in the variable.

In Java Data types are divided into two groups:

  • Primitive data types: The primitive data types include boolean, char, byte, short, int, long, float, and double.
  • Non-primitive data types: The non-primitive data types include Classes, Interfaces, and Arrays.

Here is a visual representation-

Data types

Data TypeSizeDescription
byte1 byteStores whole numbers from -128 to 127
short2 bytesStores whole numbers from -32768 to 32767
int4 bytesStores whole numbers from -2,147,483,648 to 2,147,483,647
long8 bytesStores whole numbers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
float4 bytesStores fractional numbers. Sufficient for storing 6 to 7 decimal digits
double8 bytesStores fractional numbers. Sufficient for storing 15 decimal digits
boolean1 bitStores true or false values
char2 bytesStores a single character/letter or ASCII values

N:B: Bit is the smallest segment in computer memory

1 byte = 8 bit

Primitive Data Types:


Java support 8 types of primitive data types.

Byte Data Type:

The byte data type saves memory in large arrays where the memory savings are most required. It saves space because a byte is 4 times smaller than an integer. It can also be used in place of the “int” data type.
Example:

byte variableName = 15;

Short Data Type:

The short data type can also be used to save memory, just like a byte data type. A short data type is 2 times smaller than an integer.
Example:

short variableName = 120;

Int Data Type:

The int data type is generally used as a default data type for integral values unless if there is no problem with memory.
Example:

int variableName = 456123;

Long Data Type:

The long data type is used when you need a range of values more than those provided by int.
Example:

long variableName = 2345678L;

Float Data Type:

The float data type should never be used for precise values, such as currency. Its default value is 0.0F.
Example:

float variableName = 123.54F;

Double Data Type:

The double data type is generally used for decimal values, just like float. The double data type also should never be used for precise values, such as currency. Its default value is 0.0d.
Example:

double variableName = 65.45;

Boolean Data Type:

The Boolean data type is used to store only two possible values: true and false. This data type is used for simple flags that track true/false conditions.
Example:

Boolean variableName = true;

Char Data Type:

The char data type is a single 16-bit Unicode character. Its value-range lies between ‘\u0000’ (or 0) to ‘\uffff’ (or 65,535 inclusive).The char data type is used to store characters.
Examples:

char variableName = ‘A’;

Non-Primitive Data Types:


Non-primitive data types are called reference types because they refer to objects.

The main difference between primitive and non-primitive data types are:

  • Primitive types are predefined (already defined) in Java. Non-primitive types are created by the programmer and are not defined by Java (except for String).
  • Non-primitive types can be used to call methods to perform certain operations, while primitive types cannot.
  • A primitive type always has a value, while non-primitive types can be null.
  • A primitive type starts with a lowercase letter, while non-primitive types start with an uppercase letter.
  • The size of a primitive type depends on the data type, while non-primitive types have all the same size.

Happy Learning :)