CISC 190 Chapter 10
Protected class members are denoted in a UML diagram with the symbol
#
When an "is a" relationship exists between objects, it means that the specialized object has:
all the characteristics of the general object, plus additional characteristics
If ClassA extends ClassB, then
public members in ClassB are public in ClassA, but private members in ClassB cannot be directly accessed in ClassA
What key word can you use to call a superclass constructor explicitly
super
If a class contains an abstract method:
the method will have only a header, but not a body, and end with a semicolon
When a subclass overloads a superclass method:
Both methods may be called with a subclass object
Given the following code which of the following is TRUE? public class ClassB implements ClassA{}
ClassB must override each method in ClassA.
Look at the following code. line 1 public class ClassA line 2 { line 3 public ClassA() {} line 4 public void method1() {} line 5 } line 6 public class ClassB extends ClassA line 7 { line 8 public ClassB() {} line 9 public void method1(){} line 10 } line 11 public class ClassC extends ClassB line 12 { line 13 public ClassC (){} line 14 public void method1(){} line 15 } Which method will be executed as a result of the following statements? ClassA item1=new ClassC(); item1.method1();
Line 14
Look at the following code. Which line in ClassA has an error? Line 1 public interface MyInterface Line 2 { LIne 3 int FIELDA=55; Line 4 public int method(double); LIne 5 } Line 6 public class ClassA implements MyInterface Line 7 { Line 8 FIELDA=60; Line 9 public int method(double){} Line 10}
Line 8
Replacing inadequate superclass methods with more suitable subclass methods is known as what?
Method overriding
What is required for an interface method that has a body?
The method header must begin with the key word default.
In an inheritance relationship:
The superclass constructor always executes before the subclass constructor
If ClassC extends ClassB, which extends ClassA, this would be an example of:
a chain of inheritance
Protected members are:
both not quite private and not quite public
Like a family tree, a ________ shows the inheritance relationship between classes.
class hierarchy
An anonymous inner class must:
either implement an interface or extend another class
When declaring class data members, it is best to declare them as:
private members
Which of the following statements correctly specifies three interfaces?
public class ClassA implements Interface1, Interface2, Interface3
If a class contains an abstract method
All of these Answers: you cannot create an instance of the class the method will have only a header, but not a body, and end with a semicolon the method must be overridden in subclasses
This is a special type of expression used to create an object that implements a functional interface.
lambda