It is important to state that java is a strongly type language.
We know that a variable is nothing but a named memory allocation.
A variable is defined by data type. That means the data type specify the size and type of values that can be stored.
When we want to use a variable in a program, we should first declared it as
Here a is a variable which can store integer data. int is called data type for example
A can store an integer number like 150 as
Here the value 150 is assigned to a which is called literal.
There are four basic prmitive datatypes.