Java wrapper class

1. Java wrapper class

Wrapper class Correspondence Table

Basic data types	Packing class
Byte	Byte
Boolean	Boolean
Short	Short
Char	Character
Int	Integer
Long	Long
Float	Float
Double	Double

2. Packing class Assignment (values ())

Intenger integer1 = new Integer (100);//Create a new integer object

Intenger Integer2 = 100;//is equivalent to the following values (100)

Integer Integer3 = integer.values (100); Takes 100 of the integer object in the cache, and no object is created

The Integercache class is used in integer to cache an integer object of 128-127. So the number in the-128-127 directly takes the cached integer object.

= = Basic type comparison value, object compare address, new creates an object.

3. Cache objects

Wrapper class Correspondence Table

Basic data types	Packing class
Byte	Byte (-128-127)
Boolean	Boolean (Compare String)
Short	Short (-128-127)
Char	Character (0-128)
Int	Integer (-128-127) may be extended according to configuration
Long	Long (-128-127)
Float	Float (None)
Double	Double (None)

4. Hashcode (rewrite)

Wrapper class Hashcode Returns the base type value

5. Equal (rewrite)

The basic type value of the wrapper class equal comparison

Java wrapper class