OCJP Study 02

OCJP(Java 6) 기출문제 연습 2(11~20)

PC나 스마트폰에서도 동일하게 실행되므로 장소를 가리지 않고 OCJP(JAVA 6) 국제 자격증을 목표로 학습할 수 있다.

QUESTION 11

Click the Exhibit button.
What is the result?

11. public class Person {
12. String name = "No name";
13. public Person(String nm) { name = nm; }
14. }
15.
16. public class Employee extends Person {
17. String empID = "0000";
18. public Employee(String id) { empID = id; }
19. }
20.
21. public class EmployeeTest {
22. public static void main(String[] args){
23. Employee e = new Employee("4321");
24. System.out.println(e.empID);
25. }
26. }

A. 4321
B. 0000
C. An exception is thrown at runtime.
D. Compilation fails because of an error in line 18.

D

Implicit super constructor Person() is undefined. Must explicitly invoke another constructor

QUESTION 12
Given:

1. public class Rainbow {
2. public enum MyColor {
3. RED(0xff0000), GREEN(0x00ff00), BLUE(0x0000ff);
4. private final int rgb;
5. MyColor(int rgb) { this.rgb = rgb; }
6. public int getRGB() { return rgb; }
7. };
8. public static void main(String[] args) {
9. //insert code here
10. }
11.}
Which code fragment, inserted at line 19, allows the Rainbow class to compile?

A. MyColor skyColor = BLUE;
B. MyColor treeColor = MyColor.GREEN;
C. if(RED.getRGB() < BLUE.getRGB()) { }
D. Compilation fails due to other error(s) in the code.
E. MyColor purple = new MyColor(0xff00ff);
F. MyColor purple = MyColor.BLUE + MyColor.RED;

B

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QUESTION 13
Given:
1. public class Mud {
2. //insert code here
3. System.out.println("hi");
4. }
5. }
And the following five fragments:

public static void main(String...a) {
public static void main(String.* a) {
public static void main(String... a) {
public static void main(String[]... a) {
public static void main(String...[] a) {

How many of the code fragments, inserted independently at line 2, compile?

A. 0
B. 1
C. 2
D. 3
E. 4
F. 5

D

public static void main(String...a) {
public static void main(String... a) {
public static void main(String[]... a) {

QUESTION 14
Given:

1. class Atom {
2. Atom() { System.out.print("atom "); }
3. }
4. class Rock extends Atom {
5. Rock(String type) { System.out.print(type); }
6. }
7. public class Mountain extends Rock {
8. Mountain() {
9. super("granite ");
10. new Rock("granite ");
11. }
12. public static void main(String[] a) { new Mountain(); }
13.}
What is the result?

A. Compilation fails.
B. atom granite
C. granite granite
D. atom granite granite
E. An exception is thrown at runtime.
F. atom granite atom granite

F

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QUESTION 15
Given:

interface TestA { String toString(); }

public class Test {
public static void main(String[] args) {
System.out.println(new TestA() {
public String toString() { return "test"; }
});
}
}

What is the result?

A. test
B. null
C. An exception is thrown at runtime.
D. Compilation fails because of an error in line 1.
E. Compilation fails because of an error in line 4.
F. Compilation fails because of an error in line 5.

A

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QUESTION 16
Given:

1. public static void parse(String str) {
2. try {
3. float f = Float.parseFloat(str);
4. } catch (NumberFormatException nfe) {
5. f = 0;
6. } finally {
7. System.out.println(f);
8. }
9. }
10. public static void main(String[] args) {
11. parse("invalid");
12. }
What is the result?

A. 0.0
B. Compilation fails.
C. A ParseException is thrown by the parse method at runtime.
D. A NumberFormatException is thrown by the parse method at runtime.

B

f cannot be resolved in line 5 and 7

QUESTION 17
Given:

1. public class Blip {
2. protected int blipvert(int x) { return 0; }
3. }
4. class Vert extends Blip {
5. // insert code here
6. }
Which five methods, inserted independently at line 5, will compile? (Choose five.)

A. public int blipvert(int x) { return 0; }
B. private int blipvert(int x) { return 0; }
C. private int blipvert(long x) { return 0; }
D. protected long blipvert(int x) { return 0; }
E. protected int blipvert(long x) { return 0; }
F. protected long blipvert(long x) { return 0; }
G. protected long blipvert(int x, int y) { return 0; }

A,C,E,F,G

private int blipvert(int x) { return 0; }
Cannot reduce the visibility of the inherited method from Blip
protected long blipvert(int x) { return 0; }
The return type is incompatible with Blip.blipvert(int)

QUESTION 18
Given:

1. class Super {
2. private int a;
3. protected Super(int a) { this.a = a; }
4. }
11. class Sub extends Super {
12. public Sub(int a) { super(a); }
13. public Sub() { this.a = 5; }
14. }
Which two, independently, will allow Sub to compile? (Choose two.)

A. Change line 2 to:
public int a;
B. Change line 2 to:
protected int a;
C. Change line 13 to:
public Sub() { this(5); }
D. Change line 13 to:
public Sub() { super(5); }
E. Change line 13 to:
public Sub() { super(a); }

C,D

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QUESTION 19

Which Man class properly represents the relationship "Man has a best friend who is a Dog"?

A.
class Man extends Dog { }
B.
class Man implements Dog { }
C.
class Man { private BestFriend dog; }
D.
class Man { private Dog bestFriend; }
E.
class Man { private Dog<bestfriend>; }
F.
class Man { private BestFriend<dog>; }

D

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QUESTION 20
Given:

1. package test;
2.
3. class Target {
4. public String name = "hello";
5. }
What can directly access and change the value of the variable name?

A. any class
B. only the Target class
C. any class in the test package
D. any class that extends Target

C

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