Java Chp 4
To define a class that will represent a car, which of the following definitions is most appropriate?
public class Car
A class' constructor usually defines
how an object is initialized
If a method does not have a return statement, then
it must be a void method
Instance data for a Java class
may be primitive types or objects, but objects must be defined to be private
Which of the following reserved words in Java is used to create an instance of a class?
new
The relationship between a class and an object is best described as
objects are instances of classes
If the instruction Swapper s = new Swapper(0, "hello", 0); is executed followed by s.toString( ); what value is returned from s.toString( )?
"00"
If we have Swapper r = new Swapper (5, "no", 10); then r.swap( ); returns which of the following?
"no"
A class's instance data are the variables declared in the main method
False
A constructor must always return an int
False
Formal parameters are those that appear in the method call and actual parameters are those that appear in the method header.
False
Java methods can return only primitive types (int, double, boolean, etc)
False
What part of a class is described as the state
Instance Variable
In order to preserve encapsulation of an object, we would do all of the following except for which one?
Make the class final
What part of the class is described as the behavior
Methods
Which of the following criticisms is valid about the Swapper class?
The instance data z is visible outside of Swapper
A constructor is a method that gets called automatically whenever an object is created, for example with the new operator.
True
The number and types of the actual parameters must match the number and types of the formal parameters.
True
While multiple objects of the same class can exist, there is only one version of the class.
True
Consider a method defined with the header: public void doublefoo(double x). Which of the following method calls is legal?
all of the above are legal except for d
Private
an access modifier used for attributes, methods and constructors, making them only accessible within the declared class
Public
declares a member's access as public
Consider a method defined with the header: public void foo(int a, int b). Which of the following method calls is legal?
foo(0 / 1, 2 * 3);
Void
should not have a return value
Static
the particular member belongs to a type itself, rather than to an instance of that type