midterm2023fall

What does it mean if a method is said to override another method in Java?

It means that a subclass provides a specific implementation for a method that is already defined in its superclass.

What is method overloading in Java?

Method overloading occurs when two or more methods in the same class have the same name but different parameters (type, number, or both).

What does it mean to hide a method in Java?

Hiding a method occurs when a static method in a subclass has the same name and parameters as a static method in the superclass, effectively hiding the superclass's version.

What does the `toString()` method do in Java?

The `toString()` method returns a string representation of an object.

What is an abstract class in Java?

An abstract class is a class that cannot be instantiated and may contain abstract methods that must be implemented by subclasses.

What is a checked exception in Java?

A checked exception is an exception that is checked at compile-time, and the programmer is required to handle it, typically using try-catch blocks.

What is a HashMap in Java?

HashMap is a part of Java's collection framework, implementing the Map interface, and is used for storing key-value pairs.

What is a Collection in Java?

Collection is a root interface in the Java collection framework, representing a group of objects.

What does the `public` access modifier mean in Java?

The `public` access modifier allows the class, method, or variable to be accessible from any other class.

What is the output of comparing two String objects using `==`?

The `==` operator checks for reference equality, meaning it checks if both references point to the same object.

What does `void` mean in a method signature?

The `void` keyword indicates that the method does not return any value.

What is a `Map` in Java?

A `Map` is an object that maps keys to values, allowing for retrieval with keys.

What is the purpose of the `main` method in Java?

The `main` method is the entry point of any Java application, where the program execution begins.

What are generics in Java?

Generics enable types (classes and interfaces) to be parameters when defining classes, interfaces, and methods, allowing for type safety.

What does it mean to implement an interface in Java?

Implementing an interface means a class agrees to perform the behavior defined by the methods of the interface.

What is the purpose of the `final` keyword in Java?

The `final` keyword signifies that a variable cannot be reassigned, a method cannot be overridden, or a class cannot be inherited.

What does `System.out.println` do in Java?

`System.out.println` is used to print a message to the console, followed by a new line.

What does `this` keyword refer to in Java?

The `this` keyword refers to the current object instance.

What is polymorphism in Java?

Polymorphism is a concept where a method or a function behaves differently based on the object that it is acting upon.

What does the `protected` access modifier do in Java?

The `protected` modifier allows access to a class's members by classes in the same package and subclasses.