OCJP Study 11

OCJP(Java 6) 기출문제 연습 11(101~110)

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

QUESTION 101
Given:
class Snoochy {
Boochy booch;
public Snoochy() { booch = new Boochy(this); }
}
class Boochy {
Snoochy snooch;
public Boochy(Snoochy s) { snooch = s; }
}
And the statements:
public static void main(String[] args) {
Snoochy snoog = new Snoochy();
snoog = null; //Línea 23
// more code here
}
Which statement is true about the objects referenced by snoog, snooch, and booch immediately after line 23 executes?

A. None of these objects are eligible for garbage collection.
B. Only the object referenced by booch is eligible for garbage collection.
C. Only the object referenced by snoog is eligible for garbage collection.
D. Only the object referenced by snooch is eligible for garbage collection.
E. The objects referenced by snooch and booch are eligible for garbage collection.

E

설명없음

QUESTION 102
Given:
class Payload {
private int weight;
public Payload (int w) { weight = w; }
public void setWeight(int w) { weight = w; }
public String toString() { return Integer.toString(weight); }
}
public class TestPayload {
static void changePayload(Payload p) { /* insert code */ } //Línea 12
public static void main(String[] args) {
Payload p = new Payload(200);
p.setWeight(1024);
changePayload(p);
System.out.println("p is " + p);
} }
Which code fragment, inserted at the end of line 12, produces the output p is 420?

A. p.setWeight(420);
B. p.changePayload(420);
C. p = new Payload(420);
D. Payload.setWeight(420);
E. p = Payload.setWeight(420);

A

설명없음

QUESTION 103
Given:
public static void test(String str) {
int check = 4;
if (check = str.length()) {
System.out.print(str.charAt(check -= 1) +", ");
} else {
System.out.print(str.charAt(0) + ", ");
}
}
and the invocation:
test("four");
test("tee");
test("to");
What is the result?

A. r, t, t,
B. r, e, o,
C. Compilation fails.
D. An exception is thrown at runtime.

C

It gives the error "Type mismatch: cannot convert from int to boolean" on the line with the if command because of the = instead of ==

QUESTION 104
Given classes defined in two different files:
package util;
public class BitUtils {
private static void process(byte[] b) {}
}
package app;
public class SomeApp {
public static void main(String[] args) {
byte[] bytes = new byte[256];
// insert code here Linea 5
}
}
What is required at line 5 in class SomeApp to use the process method of BitUtils?

A. process(bytes);
B. BitUtils.process(bytes);
C. app.BitUtils.process(bytes);
D. util.BitUtils.process(bytes);
E. import util.BitUtils.*; process(bytes);
F. SomeApp cannot use the process method in BitUtils.

F

Indeed because the process methos in BitUtils class is private
ZZZ

QUESTION 105
Given:
public class Pass2 {
public void main(String [] args) {
int x = 6;
Pass2 p = new Pass2();
p.doStuff(x);
System.out.print(" main x = " + x);
}
void doStuff(int x) {
System.out.print(" doStuff x = " + x++);
}
}
And the command-line invocations:
javac Pass2.java
java Pass2 5
What is the result?

A. Compilation fails.
B. An exception is thrown at runtime.
C. doStuff x = 6 main x = 6
D. doStuff x = 6 main x = 7
E. doStuff x = 7 main x = 6
F. doStuff x = 7 main x = 7

B

It gives the error "Exception in thread "main" java.lang.NoSuchMethodError: main" because the main
method isn't static
ZZZ

QUESTION 107
Given:
public class Test {
public enum Dogs {collie, harrier};
public static void main(String [] args) {
Dogs myDog = Dogs.collie;
switch (myDog) {
case collie:
System.out.print("collie ");
case harrier:
System.out.print("harrier ");
}
}
}
What is the result?

A. collie
B. harrier
C. Compilation fails.
D. collie harrier
E. An exception is thrown at runtime.

D

Tested and confirmed
ZZZ

QUESTION 107
Given:
public class Donkey {
public static void main(String[] args) {
boolean assertsOn = false;
assert (assertsOn) : assertsOn = true;
if(assertsOn) {
System.out.println("assert is on");
}
}
}
If class Donkey is invoked twice, the first time without assertions enabled, and the second time with assertions enabled, what are the results?

A. no output
B. no output
assert is on
C. assert is on
D. no output
An AssertionError is thrown.
E. assert is on
An AssertionError is thrown.

D

설명없음

QUESTION 108
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

x.toString() throws an exception because x is null
ZZZ

QUESTION 109
Given:
static void test() throws Error {
if (true) throw new AssertionError();
System.out.print("test ");
}
public static void main(String[] args) {
try { test(); }
catch (Exception ex) { System.out.print("exception "); }
System.out.print("end ");
}}
What is the result?

A. end
B. Compilation fails.
C. exception end
D. exception test end
E. A Throwable is thrown by main.
F. An Exception is thrown by main.

E

설명없음

QUESTION 110
Given:
class TestException extends Exception { }
class A {
public String sayHello(String name) throws TestException {
if(name == null) throw new TestException();
return "Hello " + name;
}
}
public class TestA {
public static void main(String[] args) {
new A().sayHello("Aiko");
}
}
Which statement is true?

A. Compilation succeeds.
B. Class A does not compile.
C. The method declared on line 9 cannot be modified to throw TestException.
D. TestA compiles if line 10 is enclosed in a try/catch block that catches TestException.

D

설명없음