Objective-wise Tests – Lambda and Functional Interfaces – 2025

Q1. Given:

List dList = Arrays.asList(10.0, 12.0);
DoubleFunction df = x->x+10;
dList.stream().forEach(df);
dList.stream().forEach(d->System.out.println(d));

What will it print when compiled and run?

Select 1 option(s):

Q2. Given :

//In Data.java
public class Data{
int value;
Data(int value){
this.value = value;
}
public String toString(){ return ""+value; }
}

and the following code fragments:
public void filterData(ArrayList dataList, Predicate p){
Iterator i = dataList.iterator();
while(i.hasNext()){
if(p.test(i.next())){
i.remove();
}
}
}
....
ArrayList al = new ArrayList();
Data d = new Data(1); al.add(d);
d = new Data(2); al.add(d);
d = new Data(3); al.add(d);

//INSERT METHOD CALL HERE
System.out.println(al);

Which of the following options can be inserted above so that it will print [1, 3]?

Select 1 option(s):

Q3. Which of the following statements are correct regarding a functional interface?

Select 1 option(s):

Q4. What will the following code print when run?

import java.util.function.Predicate;
class Employee{
int age; //1
}

public class TestClass{

public static boolean validateEmployee(Employee e, Predicate p){
return p.test(e);
}

public static void main(String[] args) {
Employee e = new Employee(); //2
System.out.println(validateEmployee(e, e->e.age<10000)); //3
}
}

Select 1 option(s):

Q5. Which of the following are correct about java.util.function.Predicate?

Select 1 option(s):

Q6. Which of the following interface definitions can use Lambda expressions?

Select 2 option(s):