Two types of entities are identified by JAVA
- Primitive
- Objects
Primitive Data Types in JAVA
- most basic types of data
- 8 primitive data types
- They have fixed size
- They are limited to range of value
- byte
- has size of 8 bits
- minimum value is -128
- maximum value is +127
- example : byte c=32;
- short
- size of 16 bits
- minimum value: -2^15
- maximum value: (2^15)-1
- example: short s=55;
- char
- size of 16 bits
- minimum value: 0
- maximum value: (2^16)-1
- All Unicode characters are char
- int
- size: 32 bits
- minimum value: 0-2^31
- maximum value: (2^31_-1
- Example: int i=25;
- long
- 64 bits size
- minimum value: (-2)^31
- maximum value: (2^31)-1
- Float
- Size: 32 bits
- minimum value: 2^-149
- maximum value: (2-2^-23)·2^127
- double
- 64 bits size
- +/-10-308 to +/-10+308 and 0, about 15 digits precision
- boolean
- True or false
Reference variables
store the address of an object
No notion of “object (physically) in the stack”
No notion of “object (physically) within an object