Interfaces - 6 questions

[madhu v pe]

Hi,
below questions are from examulator mock exam site and some from other sites which I didnot remember
6 questions on topic Interfaces
my answers were followed by 6th question.
I am having doubts specified along with answers.
you can compare with your answers and give reason why my answer is wrong?(if it is wrong)
and please clarify my doubts.

Interfaces
Q1.Which of the following is correct? Select the two correct answers. 
A.The native keyword indicates that the method is implemented in another language like C/C++. 
B.The only statements that can appear before an import statement in a Java file are comments. 
C.The method definitions inside interfaces are public and abstract. They cannot be private or protected. 
D.A class constructor may have public or protected keyword before them, nothing else. 
 
Q2.Which of the following are true about interfaces. Select the two correct answers. 
A.Methods declared in interfaces are implicitly private. 
B.Variables declared in interfaces are implicitly public, static, and final. 
C.An interface can extend any number of interfaces. 
D.The keyword implements indicate that an interface inherits from another.
 
 
   
   
Q3) Given the following code, which of the options if inserted on the line after the comment //here will allow the code to compile without error? 
class Wchapel{
    String sDescription = "Aldgate";
    public String  getDescription(){
return "Mile End";
    }
    public void output(int i ){
System.out.println(i);
    }
}
interface Liz{
 
}
public class Wfowl extends Wchapel implements Liz{
    private int i = 99;
    public static void main(String argv[]){
Wfowl wf = new Wfowl();
wf.go();
    }
    public void go(){
//here
 
    }
}
   
 

 
1)
super().output(100);
 
 
2)
new Wfowl().output(i);
 
 
3)
class test implements Liz{}
 
 
4)
System.out.println(sDescription);
 
 
5)
new Wfowl();
 
 
6)
getDescription();
 
   
Q4) Given the following code, which of the following options if inserted after the comment //here will allow the code to compile without error? 
interface Remote{
    public void  test();
 
}
public class Moodle{
    public static void main(String argv[]){
Moodle m = new Moodle();
    }
    public void go(){
//here
    }
}
1)
Remote r = new Remote(){ public void test(){} };
2)
Remote remote = new Remote();
3)
test();
4)
this.main();
 

Q5) Which of the following can legally be inserted into an interface? 
1)
public static String getPostCode();
2)
public abstract String getName();
3)
private String getAverageHousePrice();
4)
public void setPostCode(String s) { System.out.print(s); }
 
6) Which of the following is the correct syntax for suggesting that the JVM performs garbage collection? Select 1 option 
 
   
1)System.free();    
2)System.setGarbageCollection();    
3)System.out.gc();    
4)System.gc();    
 

My Answers
1) C
2)B C
3) 2,3,4,5,6
4)1my doubt is with option 2- class Moodle is not using implements Remote, can't we create an object of Remote and just leave without implementing test?
5) 1
6)4 I knew the Garbage collection is there in SCJP1.5 but, the questions will be such deeper? should we know the System class methods for exam?. I haven't seen in any books I read.

Thanks

[megha joshi]

Please check the topic Topic: Can we have inner interfaces ...!? for answers...