A summary of the Java language data types

8 Basic data Types

Data type bit byte value range

BYTE 8 1-128~127

Short 16 2-32768~32767

int 32 4-231~231-1

Long 64 8-263~263-1

Float 32 4 slightly

(Float a=3.0; C language does not error,java default to double type, need to be changed to float a=3.0f; ）

Double 64 8 slightly

Char 2 '\u0000'~'\uffff '

Boolean 1 slightly true/false

Assignment: Assigns a value directly and copies the value .

Storage location: value stored in stack

= = Operation : Binary returns true

Reference type

Defined:

Reference type except for the base data type

Including:

classes in 1.API, such as String,File

2. custom classes, such as Personalaccount,creditaccount

3. Arrays , such as int[],string[]

Application:

1. use as a type of attribute

2. Use the return value type as a method

3. use as a form parameter type for a method

Assignment Value :

use new, String to assign a value, Copy the address .

Storage location:

A reference is stored in the stack, and the property value of the specific object is stored in the heap.

= = Operation :

True if the virtual address is the same

Data type conversions

Low -> High (target type > Source Type)

Byte -> short does not error, automatic conversion;

High -> Low

Short ->byte error, forced conversion required :(byte) short -> Byte

A summary of the Java language data types