class A {
A() { }
}
class B extends A {
}
Which two statements are true?()
A. Class B’s constructor is public.
B. Class B’s constructor has no arguments.
C. Class B’s constructor includes a call to this().
D. Class B’s constructor includes a call to super().
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interface Animal {
void soundOff();
}
class Elephant implements Animal {
public void soundOff() {
System.out.println(“Trumpet”);
}
}
class Lion implements Animal {
public void soundOff() {
System.out.println(“Roar”);
}
}
class Alpha1 {
static Animal get( String choice ) {
if ( choice.equalsIgnoreCase( “meat eater” )) {
return new Lion();
} else {
return new Elephant();
}
}
}
Which compiles?()
A. new Animal().soundOff();
B. Elephant e = new Alpha1();
C. Lion 1 = Alpha.get(“meat eater”);
D. new Alpha1().get(“veggie”).soundOff();
1. class Test {
2. private Demo d;
3. void start() {
4. d = new Demo();
5. this.takeDemo(d);
6. }
7.
8. void takeDemo(Demo demo) {
9. demo = null;
10. demo = new Demo();
11. }
12. }
When is the Demo object, created on line 3, eligible for garbage collection?()
A. After line 5.
B. After line 9.
C. After the start() method completes.
D. When the takeDemo() method completes.
E. When the instance running this code is made eligible for garbage collection.
A. float[] = new float(3);
B. float f2[] = new float[];
C. float[] f1 = new float[3];
D. float f3[] = new float[3];
E. float f5[] = { 1.0f, 2.0f, 2.0f };
F. float f4[] = new float[] { 1.0f. 2.0f. 3.0f};
public class Test {
public static void main(String args[]) {
class Foo {
public int i = 3;
}
Object o = (Object)new Foo();
Foo foo = (Foo)o;
System.out.println(“i = “ + foo.i);
}
}
What is the result?()
A. i = 3
B. Compilation fails.
C. A ClassCastException is thrown at line 6.
D. A ClassCastException is thrown at line 7.
A. Java.util.Map.
B. Java.util.List.
C. Java.util.Hashable.
D. Java.util.Collection.
A. Java.util.Map.
B. Java.util.Set.
C. Java.util.List.
D. Java.util.StoredSet.
E. Java.util.StoredMap.
F. Java.util.Collection.
public class X {
public object m () {
object o = new float (3.14F);
object oa = new object [1];
oa[0]= o;
o = null;
oa[0] = null;
return o;
}
}
When is the float object created in line 3, eligible for garbage collection?()
A. Just after line 5.
B. Just after line 6.
C. Just after line 7.
D. Just after line 8(that is, as the method returns).
A. A static inner class requires a static initializer.
B. A static inner class requires an instance of the enclosing class.
C. A static inner class has no reference to an instance of the enclosing class.
D. A static inner class has access to the non-static members of the outer class.
E. Static members of a static inner class can be referenced using the class name of the static inner class.
public class MethodOver {
private int x, y;
private float z;
public void setVar(int a, int b, float c){
x = a;
y = b;
z = c;
}
}
Which two overload the setVar method?()
A. void setVar (int a, int b, float c){ x = a; y = b; z = c; }
B. public void setVar(int a, float c, int b) { setVar(a, b, c); }
C. public void setVar(int a, float c, int b) { this(a, b, c); }
D. public void setVar(int a, float b){ x = a; z = b; }
E. public void setVar(int ax, int by, float cz) { x = ax; y = by; z = cz; }
class A {
public String toString () {
return “4”;
}
}
class B extends A {
8. public String toString () {
return super.toString() + “3”;
}
}
public class Test {
public static void main(Stringargs) {
System.out.printIn(new B());
}
}
What is the result?()
A. Compilation succeeds and 4 is printed.
B. Compilation succeeds and 43 is printed.
C. An error on line 9 causes compilation to fail.
D. An error on line 14 causes compilation to fail.
E. Compilation succeeds but an exception is thrown at line 9.
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