Ex16ClassAbsInterface.java

package JavaEntry;

// abstract class: using it we hiding certain details and showing only essential information to the user.
// Interfaces, hide certain details and only show the important details of an object.

abstract class UserDetails {
 String name = "Banti Shaw";
 String universityName = "SMU";
 String getUserDetails(){
 return name + " " + universityName;
 }
}

class ForUseUserDetails extends UserDetails {
 public String getName = getUserDetails();
}

interface Student {
 String name = "Ganesh";
 String universityName = "Unknown";
 default String getStudentDetails(){
 return name;
 }
}

class ForInterfaceUse implements Student {
 public String studentName = getStudentDetails();
}

// enum is a special "class" that represents a group of constants (unchangeable variables, like final variables).
enum Process {
 TODO,
 INDEVELOPMENT,
 REVIEW,
 DONE
}

public class Ex16ClassAbsInterface {
 public static void main(String[] args){
 // UserDetails userObj = new UserDetails(); // We can't create the object with abstract class.
 ForUseUserDetails extendedUserObj = new ForUseUserDetails(); 
 System.out.println(extendedUserObj.getName);

 ForInterfaceUse interfaceStudentObj = new ForInterfaceUse();
 System.out.println(interfaceStudentObj.studentName);
 
 Process currState = Process.TODO;
 Process devState = Process.INDEVELOPMENT;
 System.out.println(currState + " " + devState);

 switch(currState){
 case TODO:
 System.out.println("Work is on " + currState + " state");
 break;
 case INDEVELOPMENT:
 System.out.println("Work is on " + currState + " state");
 break;
 case REVIEW:
 System.out.println("Work is on " + currState + " state");
 break;
 case DONE:
 System.out.println("Work is on " + currState);
 break;
 default:
 System.out.println("No Work");
 break;
 }

 for(Process enumItem : Process.values()){
 System.out.println("Process name - " + enumItem);
 }

 }
}