Question 1

The components of a class are called fields.

Accepted Answer

False

Question 2

The non-static methods of a class are called instance methods.

Accepted Answer

Instance methods require an instance of the class to be invoked and work with the instance's state.

Question 3

Modifiers are used to alter the behavior of the class.

Accepted Answer

Modifiers, such as public, private, or protected, are used to modify the behavior of classes, methods, and variables.

Question 4

Not every user-defined class can override the default definition of the method toString because it is provided by Java.

Accepted Answer

Every user-defined class in Java can override the default definition of the `toString` method because it is inherited from the `Object` class, which is the superclass of all classes in Java.

Question 5

In deep copying, each reference variable refers to its own object.

Accepted Answer

In deep copying, a new object is created for each reference variable, so each variable refers to its own object. This means that changes made to one object will not affect another object referenced by a different variable.

Question 6

Given the declaration public class MyClass
{
 private int x; public void print()
 {
 System.out.println("x = " + x);
 } private void setX(int y)
 {
 x = y;
 }
}MyClass myObject = new MyClass();The following statement is legal.myObject.setX(10);

Accepted Answer

The method setX(int y) is declared as private in the class MyClass, which means it cannot be accessed from outside the class, including from instances of the class like myObject.

Question 7

The methods of a class must be public.

Accepted Answer

The methods of a class can have different access modifiers, including public, private, protected, and package-private. However, in general, it is good practice to make only the necessary methods and fields public and keep the rest private or protected to encapsulate the class's implementation details.

Question 8

If the object is created in the definition of a method of the class, then the object can access both the public and private members of the class.

Accepted Answer

Objects created within a method of a class have access to both public and private members of the class. This is because the object is still considered to be part of the class and has access to its attributes and methods.

Question 9

An accessor method of a class first accesses the values of the data members of the class and then changes the values of the data members.

Accepted Answer

An accessor method is a method of a class that is used to access or retrieve the values of the data members, but it does not change those values. It is a read-only method. If a method changes the values of the data members, it is called a mutator method.

Question 10

Members of a class are usually classified into three categories: public, private, and static.

Accepted Answer

Members of a class are usually classified into three categories: public, private, and protected. "Static" is a modifier that can be applied to class members, but it is not a category of visibility/access like the other three.

Question 11

If a member of a class is a private method, you can access it outside the class.

Accepted Answer

Private methods can only be accessed within the class they are defined in. They cannot be accessed from outside the class.

Question 12

Given the declaration public class MyClass
{
 private int x; public void print()
 {
 System.out.println("x = " + x);
 } private void setX(int y)
 {
 x = y;
 }
}
MyClass myObject = new MyClass();The following statement is legal.myObject.print();

Accepted Answer

The statement myObject.print() is calling the public method print() of the MyClass object myObject, which will output the current value of the private variable x.

Question 13

When no object of the class type is instantiated, static data members of the class fail to exist.

Accepted Answer

Static data members are initialized when the class is loaded, not when the first object of the class is instantiated, so they exist even if no objects of the class are created.

Question 14

The method finalize automatically executes when the class object goes out of scope.

Accepted Answer

The answer of The method finalize automatically executes when the...

Question 15

A class and its members can be described graphically using Unified Modeling Language (UML) notation.

Accepted Answer

UML notation is a graphical representation used to describe software design, and it includes symbols to represent classes and their members.

Question 16

In shallow copying, each reference variable refers to its own object.

Accepted Answer

In shallow copying, only the top-level object is duplicated, and all references within the new object still refer to the original object. Therefore, each reference variable still refers to the same object.

Question 17

The default constructor executes when an object is instantiated and initialized using an existing object.

Accepted Answer

The default constructor is executed when an object is instantiated using the class name and parentheses, not when initialized using an existing object.

Question 18

The built-in operation that is valid for classes is the dot operator.

Accepted Answer

The dot operator is used to access the methods and variables of a class.

Question 19

A constructor has no type and is therefore a void method.

Accepted Answer

A constructor is a special method that doesn't have a return type, but it is not a void method. Void methods return nothing, whereas constructors create and initialize an object of a class.

Question 20

Constructors are called like any other method.

Accepted Answer

Constructors are not called directly like methods; they are called automatically when an instance of a class is created.

Quiz 8: User-Defined Classes