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double: The double data type is a double-precision 64-bit IEEE 754 floating point or 8 bytes. For
decimal values, this data type is generally the default choice. The double data type can store fractional
numbers from 1.7e−308 to 1.7e+308, i.e., values up to 16 decimal digits. Note that you may end the
value with a "d".

Type Size Default value Example
float 4 bytes 0.0f float a=10.67f;

double 8 bytes 0.0 or 0.0d double b=1234.87674;

Note: The IEEE Standard for Floating-Point Arithmetic (IEEE 754) is a technical standard for floating-
point arithmetic established in 1985 by the Institute of Electrical and Electronics Engineers (IEEE).

Char Type
It stores character constants in the memory. The char data type is a single 16-bit Unicode character. It
assumes a size of 2 bytes, but basically it can hold only a single character because char stores Unicode
character sets. It has a minimum value of ‘\u0000’ (or 0) and a maximum value of ‘\uffff’ (65,535).

Type Size Default value Example
char 2 bytes \u0000 char c='a';
char d= '\u0041';

Java uses Unicode system not ASCII code system and to represent Unicode system 8 bits is not enough
to represent all characters so java uses 16 bits or 2 bytes for characters.

Boolean 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. The boolean data type specifies one bit of information.

Type Size Default value Range of values Example
that can be stored
boolean 1 bit false true or false boolean a=true;

Note: 1. Integer type and Float type are Numeric data types.
2. Character type and Boolean type are Non-numeric Data types.

Non-Primitive Data Type

They are also called Reference Data Types or Composite Data types. They contain a memory address
of variable value because the reference types won’t store the variable value directly in memory. They
are defined by the programmer according to the requirement of the program. Different types of Non-
Primitive data types are strings, objects, arrays and interfaces.

Difference between Primitive Data Type and Non-Primitive Data Type

Primitive Data Type Non-Primitive Data Type
They are built-in data types. They are used defined data types.

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