Quiz Java Par Khaled HALLEB, Consultant OLBATI Au Geek Time de Janvier 2017

1. Quiz Java
Geek Time - Janvier 2017
Khaled HALLEB
Consultant - OLBATI

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Question 1
TreeMap class is used to implement which collection interface. Select the one correct answer
A. Set
B. SortedSet
C. List
D. Tree
E. SortedMap

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Question 2
Q2. How can you force garbage collection of an object?
A. Garbage collection cannot be forced.
B. Call System.gc().
C. Call System.gc() passing in a reference to the object to be garbage collected.
D. Call Runtime.gc().
E. Set all references to the object to new values(null, for example).

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Question 3
3. Given the following code:
public class Example {
public static void main(String args[]) {
Date d1 = new Date (99, 11, 31);
Date d2 = new Date (99, 11, 31);
method(d1, d2);
System.out.println("d1 is " + d1
+ "nd2 is " + d2);
}
public static void method(Date d1, Date d2) {
d2.setYear (100);
d1 = d2;
}}
Which one or more of the following correctly describe the behavior when this
program is compiled and run?
a) compilation is successful and the output is:
d1 is Fri December 31 00:00:00 GMT 1999
d2 is Fri December 31 00:00:00 GMT 1999
b) compilation is successful and the output is:
d1 is Fri December 31 00:00:00 GMT 1999
d2 is Sun December 31 00:00:00 GMT 2000
c) compilation is successful and the output is:
d1 is Sun December 31 00:00:00 GMT 2000
d2 is Sun December 31 00:00:00 GMT 2000
d) the assignment 'd1 = d2' is rejected by the compiler because the Date class cannot overload the operator '='.
e) the expression (d1 is " + d1 + "nd2 is " + d2) is rejected by the compiler because the Date class cannot overload the
operator '+'.

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Réponse 1
TreeMap class is used to implement which collection interface. Select the one correct answer
Correct Answer: E

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Réponse 2
Q2. How can you force garbage collection of an object?
Correct Answer: A

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Réponse 3
3. Given the following code:
public class Example {
public static void main(String args[]) {
Date d1 = new Date (99, 11, 31);
Date d2 = new Date (99, 11, 31);
method(d1, d2);
System.out.println("d1 is " + d1
+ "nd2 is " + d2);
}
public static void method(Date d1, Date d2) {
d2.setYear (100);
d1 = d2;
}}
Correct Answer: B

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Thanks !
Any questions ?
khaled.halleb@olbati.com