Question

Using the interface and class definitions below, write the headings of all of the methods which still need to be defined in the class Class2.

https://hastebin.com/kopejolila.java

 public interface Interface1 { 
     public float method1(int i) ;
  }

  public interface Interface2 extends Interface1 {
     public int method2(int i) ; 
     public void method3(int i) ; 
  } 

  public abstract class Class1 {
     public float method1(int anInt) {
        return anInt * 2.0f ;
     } 
     public abstract void method3(Object anObject) ; 
     public abstract void method4(int anInt) ; 
  }

  public class Class2 extends Class1 implements Interface2 {  
     public void method3(int anInt) {
        System.out.println(anInt) ;
     }
       What other method headings need to be defined here?
  }

List the headings of methods that still must be defined in Class2 in the box below so that Class2 will compile.

Answer 1

Answer.)

To Compile Class 2, the below methods needs to be overridden :

• public int method2(int i)
• public void method3(Object anObject)
• public void method4(int anInt)

Explanation: As Class 2 extends Class 1, which already has the implementation of method1(), it is not required to override. However, method3(Object anObject) of Class 1 needs to be overridden as the method arguments are different as implemented in Class 2. Also, as Class 2 implements Interface 2 and extends Class 1, so abstract methods - method2(int I) of Interface 2 and method4(int anInt) of Class 1 needs to be implemented.