Instance variables, Local variables and Method Parameters

Instance variables:

-are mainly use to store objects's state 

-visibility can be controlled by using appropriate scope (public, private, protected,default)

-lifetime is limited to containing object's lifetime

Local variables and Method parameters:
-are local to specific method 
-visibility can not be controlled its only visible inside the defined method-lifetime is temporary and only limited to method scope

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Example: To demonstrate different types of variables

public class Customer {   

     private String lastName; //instance variable

     private String firstName; //instance variable

    

     public String getLastName() {

          return lastName;

     }

     public void setLastName(String lName) { //parameter 

          lastName = lName;

     }

     public String getFirstName() {

          return firstName;

     }

     public void setFirstName(String fName) {

          firstName = fName;

     }

     //Returns full name by concatenating Last and First name

     public String getFullName() {

          String fullName; //local variable

          fullName = getLastName() + " " + getFirstName();

          return fullName;

     }

}