During programming, you might need an entity to store some value into it for this you can use variables. Each variable has a capacity that is determined by the data type assigned to it during declaration.
The name assigned to a memory location is known as a variable. Java provides two types of variables-
The name we choose for a variable, methods, classes, interfaces, and packages is called an identifier.
The data type determines the maximum value a variable can store. There are two type of data types in Java-
A type of value a variable can store is also determined by the data type.
Following table displays the size, range, and default value of primitive data types.
|Data Type||Size||Range||Default Value|
|boolean||1 bit||true or false||false|
|byte||1 byte||-128 to 127||0|
|short||2 byte||-32768 to 32767||0|
|char||2 byte||0 to 65535||'\u0000'|
|int||4 byte||-231 to 231 - 1||0|
|long||8byte||-263 to 263 - 1||0L|
|float||4 byte||-231 to 231 - 1||0.0f|
|double||8 byte||-263 to 263 - 1||0.0d|
Without initialization, a variable holds default value which is listed above in the table. Also, you can initialize variables at the time of declaration.
int a = 10; //We are doing initialization at the point of declaration. int b; //We are only declaring it. b = 12; //Later we initialize variable b with 12.