APCSA Unit 5 refresher

The return type of an accessor method

• is void

• must be a user defined class

• must be a primitive

• must match the type of the instance variable being accessed

The purpose of an accessor method is

• to modify an instance variable

• to return the value of an instance variable

• to return the values of all of the instance variables

• to allow the user to have direct access to an instance variable

Which of the following is true?

• Both primitives and objects are returned by value.

• Both primitives and objects are returned by reference.

• Primitives are returned by value. Objects are returned by reference.

• Objects are returned by value. Primitives are returned by reference.

Accessors and mutators are used to

• Allow private data to be accessed outside of the class and be safely modified.

• Allow users to access and modify any of the class’s data in any way they wish.

• Prevent users from manipulating private data.

• Allow public data to be accessed and safely modified.

The return type of a mutator method

• is usually void

• must match the type of of the instance variable being mutated

• must be a primitive

• must be a user defined class

Which of the following is a benefit of using a mutator method?

• Only methods outside of the class can change an instance variable’s value

• Mutator methods can verify the new value is a valid value for the instance variable

• The user can change all of the instance variables using the same mutator method

Classes’ access specifier is generally set to

• private to prevent any user from accessing and modifying any instance variables.

• private so that only certain users can create objects of the class.

• public so that all data and methods are accessible by any user.

• public so that any user can create and use objects of the class.

What is the difference between a getter method and an accessor method?

• A getter method allows you to get the value of a field while an accessor method is not often used in Java.

• A getter method gets the name of the class while an accessor method gets the value of the field.

• There is no difference. They refer to the same idea.

Which of the following is NOT a characteristic of a mutator?

• The method changes the value of an instance variable to a user’s specified value

• The method’s name (usually) starts with set

• The method’s name (usually) starts with set

• The method returns the value of an instance variable

The purpose of a mutator method is

• to return the value of an instance variable

• to safely modify an instance variable

• to return the values of all of the instance variables

• to allow the user to have direct access to an instance variable