Variable and DataTypes in java

Variable:

Variable is the name of reserved memory location. It means when we declare a variable some part of memory is reserved.

e.g. int var1 = 35;

var1 is a variable here.

Variable Types:

Local variable:

A variable that is declared within the method, constructor, or block is known as local variable.

No Access modifier is used for local variables. Scope of local variable is limited to that method, constructor, or block only in which it declared.

Instance variable:

A variable that is declared within the class but outside of method, constructor, or block is known as instance variable (Non static). They are associated with object. Access modifiers can be used with instance variables. Inside class you can access instance variable direct by variable name without any object reference.

Static variable:

A variable that is declared within the class with static keyword but outside of method, constructor, or block is known as Static/class variable. They are associated with class. Static variable are accessed by ClassName.VariableName.

 Data types:

As we discussed when a variable is declared some part of memory is reserved. But how much memory will be reserved. It depends upon the data type of the variable.  i.e. how much memory will be reserved and which type of data can be stored in reserved memory is depends upon data type of the variable.

Primitive data types:

Primitive data types are predefined in the language.

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