Oracle 1Z0-853 問題集

質問 1：
Given:
1.public class Drink implements Comparable {
2.public String name;
3.public int compareTo(Object o) {
4.return 0;
5.}
6.}
and:
20.
Drink one = new Drink();
21.
Drink two = new Drink();
22.
one.name= "Coffee";
23.
two.name= "Tea";
23.
TreeSet set = new TreeSet();
24.
set.add(one);
25.
set.add(two);
A programmer iterates over the TreeSet and prints the name of each Drink object.
What is the result?
A. The code runs with no output.
B. An exception is thrown at runtime.
C. Compilation fails.
D. Coffee
E. Tea
F. Coffee Tea
正解：D

質問 2：
Given:
12.
public class Yippee2 {
13.
14.
static public void main(String [] yahoo) {
15.
for(int x = 1; x < yahoo.length; x++) {
16.
System.out.print(yahoo[x] + " ");
17.
}
18.
}
19.
}
and the command line invocation:
java Yippee2 a b c
What is the result?
A. a b c
B. b c
C. An exception is thrown at runtime.
D. Compilation fails.
E. a b
正解：B

質問 3：
Given:
10.
class Line {
11.
public static class Point {}
12.
}
13.
14.
class Triangle {
15.
// insert code here
16.
}
Which code, inserted at line 15, creates an instance of the Point class defined in Line?
A. Line l = new Line() ; l.Point p = new l.Point();
B. The Point class cannot be instatiated at line 15.
C. Line.Point p = new Line.Point();
D. Point p = new Point();
正解：C

質問 4：
Given classes defined in two different files:
1.package packageA;
2.public class Message {
3.String getText() { return "text"; }
4.}
and:
1.package packageB;
2.public class XMLMessage extends packageA.Message {
3.String getText() { return "<msg>text</msg>";}
4.public static void main(String[] args) {
5.System.out.println(new XMLMessage().getText());
6.}
7.}
What is the result of executing XMLMessage.main?
A. Compilation fails because of an error in line 3 of XMLMessage.
B. text
C. Compilation fails because of an error in line 2 of XMLMessage.
D. An exception is thrown at runtime.
正解：A

質問 5：
A class games.cards.Poker is correctly defined in the jar file Poker.jar. A user wants to
execute the main method of Poker on a UNIX system using the command:
java games.cards.Poker
What allows the user to do this?
A. Put Poker.jar in directory /stuff/java, and set the CLASSPATH to include /stuff/java/Poker.jar
B. put Poker.jar in directory /stuff/java/games/cards, and set the CLASSPATH to include /stuff/java/Poker.jar
C. put Poker.jar in directory /stuff/java/games/cards, and set the CLASSPATH to include /stuff/java/*.jar
D. put Poker.jar in directory /stuff/java/games/cards, and set the CLASSPATH to include /stuff/java
E. put Poker.jar in directory /stuff/java, and set the CLASSPATH to include /stuff/java
F. put Poker.jar in directory /stuff/java, and set the CLASSPATH to include /stuff/java/*.jar
正解：A

質問 6：
Click the Exhibit button.
Which code, inserted at line 14, will allow this class to correctly serialize and deserialize?

A. x = s.readInt(); y = s.readInt();
B. y = s.readInt(); x = s.readInt();
C. this = s.defaultReadObject();
D. s.defaultReadObject();
正解：A