interface Beta {}
class Alpha implements Beta {
String testIt() {
return “Tested”;
}
}
public class Main1 {
static Beta getIt() {
return new Alpha();
}
public static void main( String[] args ) {
Beta b = getIt();
System.out.println( b.testIt() );
}
}
What is the result?()
A. Tested
B. Compilation fails.
C. The code runs with no output.
D. An exception is thrown at runtime.
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1. class Bar { }
1. class Test {
2. Bar doBar() {
3. Bar b = new Bar();
4. return b;
5. }
6. public static void main (String args[]) {
7. Test t = new Test();
8. Bar newBar = t.doBar();
9. System.out.println(“newBar”);
10. newBar = new Bar();
11. System.out.println(“finishing”);
12. }
13. }
At what point is the Bar object, created on line 3, eligible for garbage collection?()
A. After line 8.
B. After line 10.
C. After line 4, when doBar() completes.
D. After line 11, when main() completes.
1. public class A {
2. void A() {
3. System.out.println(“Class A”);
4. }
5. public static void main(String[] args) {
6. new A();
7. }
8. }
What is the result?()
A. Class A
B. Compilation fails.
C. An exception is thrown at line 2.
D. An exception is thrown at line 6.
E. The code executes with no output.
20. public float getSalary(Employee e) {
21. assert validEmployee(e);
22. float sal = lookupSalary(e);
23. assert (sal>0);
24. return sal;
25. }
26. private int getAge(Employee e) {
27. assert validEmployee(e);
28. int age = lookupAge(e);
29. assert (age>0);
30. return age;
31. }
Which line is a violation of appropriate use of the assertion mechanism?()
A. line 21
B. line 23
C. line 27
D. line 29
1. class Exc0 extends Exception { }
2. class Exc1 extends Exc0 { }
3. public class Test {
4. public static void main(String args[]) {
5. try {
6. throw new Exc1();
7. } catch (Exc0 e0) {
8. System.out.println(“Ex0 caught”);
9. } catch (Exception e) {
10. System.out.println(“exception caught”);
11. }
12. }
13. }
What is the result?()
A. Ex0 caught
B. exception caught
C. Compilation fails because of an error at line 2.
D. Compilation fails because of an error at line 6.
A. public
B. private
C. protected
D. transient
E. default access
public class X {
public static void main(String [] args) {
try {
badMethod();
System.out.print(“A”);
}
catch (Exception ex) {
System.out.print(“C”);
}
finally {
System.out.print(“B”);
}
System.out.print(“D”);
}
public static void badMethod() {
throw new Error();
}
}
What is the result?()
A. ABCD
B. Compilation fails.
C. C is printed before exiting with an error message.
D. BC is printed before exiting with an error message.
E. BCD is printed before exiting with an error message.
public class X {
public X aMethod() { return this;}
}
public class Y extends X {
}
Which two methods can be added to the definition of class Y?()
A. public void aMethod() {}
B. private void aMethod() {}
C. public void aMethod(String s) {}
D. private Y aMethod() { return null; }
E. public X aMethod() { return new Y(); }
A. assert (!(map.contains(x))); map.add(x);
B. if (x > 0){}else { assert (x==0); }
C. public void aMethod(int x) { assert (x > 0); }
D. assert (invariantCondition()); return retval;
E. switch (x) { case 1: break; case 2: creak; default: assert (x == 0);
int i = 1,j = 10;
do{
if (i>j) {
continue;
}
j--;
} while (++i <6);
System.out.println(“i = “ +i+” and j = “+j);
What is the result?()
A. i = 6 and j = 5
B. i = 5 and j = 5
C. i = 6 and j = 4
D. i = 5 and j = 6
E. i = 6 and j = 6
class Super {
public int i = 0;
public Super(String text) {
i = 1;
}
}
public class Sub extends Super {
public Sub(String text) {
i = 2;
}
public static void main(String args[]) {
Sub sub = new Sub(“Hello”);
System.out.println(sub.i);
}
}
What is the result?()
A. 0
B. 1
C. 2
D. Compilation fails.
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