Questions
Welcome
I recommend that you also make use of my online Java tutorial lessons, which are designed from a more conventional textbook approach. Those tutorial lessons are published at Gamelan.com.
For your convenience, I also maintain a consolidated Table of Contents on my personal web site that links to the individual lessons on the Gamelan site.
Insofar as possible, I will make use of Sun Java in these lessons. However, it will not be possible for me to go back and do a full update each time Sun releases a new version, so over the course of time, I expect to use different versions of Sun Java.
Just in case you would like to sneak a peek, the answers to the questions, and the explanations of those answers are located (in reverse order) at the end of this file.
The questions and the answers are connected by hyperlinks to make it easy for you to navigate from the question to the answer and back. It is recommended that you make your first pass through the questions in the order that they appear so as to avoid inadvertently seeing the answer to a question before you provide your own answer.
1. True or false? Any of the access modifiers, public, protected, or private, can be applied to a top-level class.
2. Which, if any, of the following declarations are legal?
- A. public MyClass {//…}
- B. public protected int myVar;
- C. friendly Button myButton;
- D. Label myLabel;
3. True or false? Access modifiers control which classes may use a feature. A class’ features are:
- The class itself.
- Its class variables.
- Its methods and constructors
4. True or false? Top-level classes that are declared private may be accessed only by other classes in the same package.
5. What output is produced by the following program?
- A. A compiler error
- B. A runtime error
- C. 15
class Q19{ |
6. What output is produced by the following program?
- A. A compiler error
- B. A runtime error
- C. 15
class Q21{ |
7. True or false? friendly is a Java keyword that is used to specify a level of access.
8. Preface: Friendly is the name given by Roberts, Heller, and Ernest, to the default access of classes, variables, and methods. If you don’t specify an access modifier such as public, private, or protected, it is said to be friendly.
True or false? A class’s friendly features are directly accessible to any class in the same package as the class in question. (In this case, directly accessible means that it is not necessary to go through a public member to gain access.)
9. True or false? The Java runtime environment considers that all class files in its current working directory constitute a package.
10. What output is produced by the following program?
- A. A compiler error
- B. A runtime error
- C. 15
class Q31{ |
Copyright 2000, Richard G. Baldwin. Reproduction in whole or in part in any form or medium without express written permission from Richard Baldwin is prohibited.
About the author
Richard Baldwin is a college professor and private consultant whose primary focus is a combination of Java and XML. In addition to the many platform-independent benefits of Java applications, he believes that a combination of Java and XML will become the primary driving force in the delivery of structured information on the Web.
Richard has participated in numerous consulting projects involving Java, XML, or a combination of the two. He frequently provides onsite Java and/or XML training at the high-tech companies located in and around Austin, Texas. He is the author of Baldwin’s Java Programming Tutorials, which has gained a worldwide following among experienced and aspiring Java programmers. He has also published articles on Java Programming in Java Pro magazine.
Richard holds an MSEE degree from Southern Methodist University and has many years of experience in the application of computer technology to real-world problems.
Answers and Explanations
Answer 10
Explanation 10
Answer 9
The answer is true.
Explanation 9
Answer 8
Explanation 8
Answer 7
Explanation 7
Answer 6
Explanation 6
Answer 5
The answer is C, 15.
Explanation 5
Answer 4
False.
Explanation 4
Answer 3
True according to The Complete Java 2 Certification Study Guide, by Roberts, Heller, and Ernest.
Explanation 3
Answer 2
Explanation 2
Answer 1
Explanation 1
Copyright 2000, Richard G. Baldwin. Reproduction in whole or in part in any form or medium without express written permission from Richard Baldwin is prohibited.
About the author
Richard Baldwin is a college professor and private consultant whose primary focus is a combination of Java and XML. In addition to the many platform-independent benefits of Java applications, he believes that a combination of Java and XML will become the primary driving force in the delivery of structured information on the Web.
Richard has participated in numerous consulting projects involving Java, XML, or a combination of the two. He frequently provides onsite Java and/or XML training at the high-tech companies located in and around Austin, Texas. He is the author of Baldwin’s Java Programming Tutorials, which has gained a worldwide following among experienced and aspiring Java programmers. He has also published articles on Java Programming in Java Pro magazine.
Richard holds an MSEE degree from Southern Methodist University and has many years of experience in the application of computer technology to real-world problems.