Which data structure in Java is based on the Last-In-First-Out (LIFO) principle?

Which design pattern is used to create objects without exposing the instantiation logic to the client?

A. Factory Method

B. Singleton

C. Builder

D. Prototype

In Java, which keyword is used to explicitly call the superclass constructor?

A. parent()

B. extends

C. this()

D. super()

What is the output of the following code snippet in Java? `System.out.println("5 + 2 = " + 5 + 2);`

A. 5 + 2 = 7

B. 7

C. 5 + 2 = 52

D. Compilation Error

What is the purpose of the `hashCode()` method in Java's Object class?

A. To execute SQL queries

B. To return a unique identifier for an object

C. To create JavaBeans

D. None of These