java

Java Data Types

Posted by

ADMIN

On January 24, 2025

Data Type	Size	Default Value	Description
byte	1 byte	`0`	Stores whole numbers from -128 to 127.
short	2 bytes	`0`	Stores whole numbers from -32,768 to 32,767.
int	4 bytes	`0`	Stores whole numbers from -2,147,483,648 to 2,147,483,647.
long	8 bytes	`0L`	Stores whole numbers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807. Add `L` or `l` suffix for long literals (e.g., `1234L`).
float	4 bytes	`0.0f`	Stores fractional numbers. Precision: Up to 7 decimal digits. Add `f` or `F` suffix for float literals (e.g., `3.14f`).
double	8 bytes	`0.0d`	Stores fractional numbers. Precision: Up to 15 decimal digits. Add `d` or `D` suffix for double literals (e.g., `3.14159d`).
char	2 bytes	`'\u0000'`	Stores a single 16-bit Unicode character. Example: `'A'` or `'\u0041'`.
boolean	1 bit (not precisely defined)	`false`	Stores true or false. Size depends on JVM implementation (typically 1 bit or 1 byte).

Type	Size	Default Value	Description
String	Depends on content	`null`	Stores a sequence of characters. Immutable (cannot be changed after creation).
Arrays	Depends on length & type	`null`	Stores a collection of elements of the same type.
Class	Depends on object fields	`null`	Represents user-defined types.
Interface	N/A	`null`	Represents a contract that classes can implement.

Wrapper Classes: Each primitive type has a corresponding wrapper class (Byte, Short, Integer, Long, Float, Double, Character, Boolean) to use primitives as objects.
Default Values: Non-primitive data types default to null.
Ranges of Integer Types: Derived from -2^(n-1) to 2^(n-1)-1, where n is the number of bits.
Floating-Point Representation: Based on IEEE 754 standard.
Type Conversion: Implicit conversions (widening) occur in compatible types (e.g., int to long), but explicit casting is required for narrowing (e.g., double to float).