In Java, objects are stored with their states in variables. They are acting as containers to hold values during object’s life scope.
How to declare a variable?
To declare variable, we require to assign some data type for that variable. Data type defines what kind of value this variable can hold (int, long ,float,String etc.).Variable names are case-sensitive.
What is the scope of a variable?
1) Instance Variable
Syntax
ClassScope ClassName {
DataType varName;
}
Example
class Person{
String personName;
}
Here, personName is an instance variable, Each instance of class Person will have separate copy for personName.
2) Class variable
Syntax
ClassScope ClassName {
static DataType varName;
}
Example
class Person{
static String personName;
}
Here, personName is a class variable, It is also known as static variable, All instances of class Person will share the same personName attribute.
3) Local Variables
Syntax
ReturnType MethodName{
DataType localVariable;
}
Example
void showLocalVariable(){
String personName;
}
Here, personName is a local variable, its scope is within method only.
4) Parameters
Syntax
ReturnType showParameter(DataType1 parameter1,DataType2 parameter2,..,DataType3 parametern){
//logic part of this method.
}
Example
int addition(int firstNumber,int secondNumber){
return firstNumber+secondNumber;
}
