1Z0-811 Core Java API

Question 1

What is the output of the following code? import java.util.*;
public class Test {
public static void main(String[] args) {
List list = Arrays.asList("A", "B", "C");
list.add("D");
}
}

Accepted Answer

Compilation error

Answer

Runtime error

Answer

The list will contain ["A", "B", "C", "D"]

Answer

The list will contain ["A", "B", "C"] and "D" will not be added

Question 2

Which interface in the Java Collections Framework represents a collection of elements that allows for duplicates and maintains insertion order?

Accepted Answer

List

Answer

Set

Answer

Queue

Answer

Map

Question 3

Which of the following classes is part of the Java Collections Framework and provides constant-time performance for the basic operations?

Accepted Answer

HashSet

Answer

LinkedList

Answer

ArrayList

Answer

TreeSet

Question 4

How does the Java Streams API improve the processing of collections?

Accepted Answer

By enabling parallel processing of elements

Answer

By allowing operations to be performed only sequentially

Answer

By modifying the underlying collection directly

Answer

By storing elements in sorted order

Question 5

What does the "java.util.concurrent" package primarily provide?

Accepted Answer

Utilities for concurrent programming and synchronization

Answer

Utilities for file and I/O operations

Answer

Utilities for network communication

Answer

Utilities for database access

What is the output of the following code? import java.util.*; public class Test { public static void main(String[] args) { List list = Arrays.asList("A", "B", "C"); list.add("D"); } }

What is the output of the following code?
import java.util.*;
public class Test {
public static void main(String[] args) {
List list = Arrays.asList("A", "B", "C");
list.add("D");
}
}