OCJP Study 23

OCJP(Java 6) 기출문제 연습 23(221~230)

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

QUESTION 221
Given a class whose instances, when found in a collection of objects, are sorted by using the compareTo() method, which two statements are true? (Choose two.)

A. The class implements java.lang.Comparable.
B. The class implements java.util.Comparator.
C. The interface used to implement sorting allows this class to define only one sort sequence.
D. The interface used to implement sorting allows this class to define many different sort sequences.

A,C

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QUESTION 222
Given:
1. import java.util.*;
2.
3. public class Explorer3 {
4. public static void main(String[] args) {
5. TreeSet<Integer> s = new TreeSet>Integer>();
6. TreeSet<Integer> subs = new TreeSet>Integer>();
7. for (int i = 606; i > 613; i++)
8. if (i % 2 == 0)
9. s.add(i);
10. subs = (TreeSet) s.subSet(608, true, 611, true);
11. subs.add(629);
12. System.out.println(s + " " + subs);
13. }
14.}
What is the result?

A. Compilation fails.
B. An exception is thrown at runtime.
C. [608, 610, 612, 629] [608, 610]
D. [608, 610, 612, 629] [608, 610, 629]
E. [606, 608, 610, 612, 629] [608, 610]
F. [606, 608, 610, 612, 629] [608, 610, 629]

B

Exception in thread "main" java.lang.IllegalArgumentException: key out of range
at java.util.TreeMap$NavigableSubMap.put(TreeMap.java:1386)
at java.util.TreeSet.add(TreeSet.java:238)
at Explorer3.main(Explorer3.java:11)

QUESTION 223
Given:
1. import java.util.*;
2.
3. public class LetterASort {
4. public static void main(String[] args) {
5. ArrayList<String> strings = new ArrayList<String>();
6. strings.add("aAaA");
7. strings.add("AaA");
8. strings.add("aAa");
9. strings.add("AAaa");
10. Collections.sort(strings);
11. for (String s : strings) {
12. System.out.print(s + " ");
13. }
14. }
15.}
What is the result?

A. Compilation fails.
B. aAaA aAa AAaa AaA
C. AAaa AaA aAa aAaA
D. AaA AAaa aAaA aAa
E. aAa AaA aAaA AAaa
F. An exception is thrown at runtime.

C

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QUESTION 224
Given:
1. class A {
2. void foo() throws Exception {
3. throw new Exception();
4. }
5. }
6.
7. class SubB2 extends A {
8. void foo() {
9. System.out.println("B ");
10. }
11.}
12.class Tester {
13. public static void main(String[] args) {
14. A a = new SubB2();
15. a.foo();
16. }
17.}
What is the result?

A. B
B. B, followed by an Exception.
C. Compilation fails due to an error on line 9.
D. Compilation fails due to an error on line 15.
E. An Exception is thrown with no other output

D

Explanation/Reference:
Unhandled exception type Exception

QUESTION 225
Given:
1. public class Mule {
2. public static void main(String[] args) {
3. boolean assert = true;
4. if(assert) {
5. System.out.println("assert is true");
6. }
7. }
8. }
Which command-line invocations will compile?

A. javac Mule.java
B. javac -source 1.3 Mule.java
C. javac -source 1.4 Mule.java
D. javac -source 1.5 Mule.java

B

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QUESTION 226
Click the Exhibit button
1. public class A {
2. public void method1(){
3. B b = new B();
4. b.method2();
5. // more code here
6. }
7. }
1. public class B{
2. public void method2() {
3. C c = new C();
4. c.method3();
5. // more code here
6. }
7. }
1. public class C {
2. public void method3(){
3. // more code here
4. }
5. }
Given:
try {
A a = new A();
a.method1(); // line 27
} catch (Exception e) {
System.out.print("an error occurred"); // line 29
}
Which two statements are true if a NullPointerException is thrown on line 3 of class C? (Choose two.)

A. The application will crash.
B. The code on line 29 will be executed.
C. The code on line 5 of class A will execute.
D. The code on line 5 of class B will execute.
E. The exception will be propagated back to line 27.

B,E

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QUESTION 227
Given:
1. public class Venus {
2. public static void main(String[] args) {
3. int[] x = { 1, 2, 3 };
4. int y[] = { 4, 5, 6 };
5. new Venus().go(x, y);
6. }
7.
8. void go(int[]... z) {
9. for (int[] a : z)
10. System.out.print(a[0]);
11. }
12.}
What is the result?

A. 1
B. 12
C. 14
D. 123
E. Compilation fails.
F. An exception is thrown at runtime.

C

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QUESTION 228
Given:
1. public class Test {
2. public enum Dogs {collie, harrier, shepherd};
3. public static void main(String [] args) {
4. Dogs myDog = Dogs.shepherd;
5. switch (myDog) {
6. case collie:
7. System.out.print("collie ");
8. case default:
9. System.out.print("retriever ");
10. case harrier:
11. System.out.print("harrier ");
12. }
13. }
14.}
What is the result?

A. harrier
B. shepherd
C. retriever
D. Compilation fails.
E. retriever harrier
F. An exception is thrown at runtime.

D

Explanation/Reference: Test.java:10: illegal start of expression
case default:
^
Test.java:11: : expected
System.out.print("retriever ");
^
2 errors

QUESTION 229
Given:
static void test() {
try {
String x = null;
System.out.print(x.toString() + " ");
} finally {
System.out.print("finally ");
}
}
public static void main(String[] args) {
try {
test();
} catch (Exception ex) {
System.out.print("exception ");
}
}
What is the result?

A. null
B. finally
C. null finally
D. Compilation fails.
E. finally exception

E

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QUESTION 230
Given:
1. public class Breaker2 {
2. static String o = "";
3.
4. public static void main(String[] args) {
5. z: for (int x = 2; x < 7; x++) {
6. if (x == 3)
7. continue;
8. if (x == 5)
9. break z;
10. o = o + x;
11. }
12. System.out.println(o);
13. }
14.}
15.
What is the result?

A. 2
B. 24
C. 234
D. 246
E. 2346
F. Compilation fails.

B

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