This section contains the details about data types in java
Basic Data Types
When variables declared, system reserved some space to store value .
In Java there are two data types :
1.Primitive Data types.
2.Refrence Data types.
Primitive Data Type
Java support 8 primitive data types, they are predefined and all of these have predefined keywords. Eight data types are as follows :
- Byte is a 8 bit data type
- It's range is -128 to 127.
- It's default value is zero.
- It is the smallest java integer type. Byte is four times smaller than an int.
- Example : byte x = 90, byte y =- 60.
- Short is 16 bit signed type.
- It's range is 32,768 to 32,767.
- Default value is 0.
- Short is 2 times smaller than an int.
- Example :short s= 20000 , short r = -30000
- Int is a 32-bit data type.
- It's range is from 2,147,483,648 to 2,147,483,647.
- For integral value int is generally used.
- Default value is 0.
- Example : int a = 200000, int b = -300000.
- Long is 64 bit data type.
- It's range is -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.
- Long is used where we need to store a wider range data than int.
- It's default value is 0L.
- Example : int a = 100000L, int b = -200000L.
- Double is used ,when fractional precision calculation is required.
- It is 64 bit double precision data type.
- It's default value is Default value is 0.0d.
- Example : double d = 123.4.
- float is 32 bit single precision type.
- It is used when fractional precision calculation is required.
- Default value is 0.0f.
- Example : float f1 = 234.5f.
- When we need to represent one bit of information, we use Boolean data type.
- It takes two values true and false.
- It is generally used where we need to track true/false conditions.
- Default value is false.
- Example : Boolean one = true.
- char is 16 bit type and used to represent Unicode characters.
- Range of char is 0 to 65,536.
- Example . char letter ='A' .
Reference Data Types :
- Reference data types or objects are created using class constructors. It's type can't be changed after declaration.
- Default value of any reference variable is null.
- A reference variable can be used to refer to any object of the declared type or any compatible type.
- Example : Mainclass mc = new Mainclass("Ankit") .