Declarations and Access Control - Practice Questions

Question 1

public class Test { }

What is the prototype of the default constructor?

Accepted Answer

Question 2

Which three are valid method signatures in an interface?

    private int getArea();
    public float getVol(float x);
    public void main(String [] args);
    public static void main(String [] args);
    boolean setFlag(Boolean [] test);

Accepted Answer

Question 3

Which three form part of correct array declarations?
1. public int a [ ]
     2. static int [ ] a
     3. public [ ] int a
     4. private int a [3]
     5.private int [3] a [ ]
    6. public final int [ ] a

Accepted Answer

Question 4

What is the narrowest valid returnType for methodA in line 3?

public class ReturnIt 
{ 
    returnType methodA(byte x, double y) /* Line 3 */
    { 
        return (long)x / y * 2; 
    } 
}

Accepted Answer

Question 5

Which two cause a compiler error?

    float[ ] f = new float(3);
    float f2[ ] = new float[ ];
    float[ ]f1 = new float[3];
    float f3[ ] = new float[3];
    float f5[ ] = {1.0f, 2.0f, 2.0f};

Accepted Answer

Question 6

You want subclasses in any package to have access to members of a superclass. Which is the most restrictive access that accomplishes this objective?

Accepted Answer

Question 7

Which two of the following are legal declarations for nonnested classes and interfaces?

    final abstract class Test {}
    public static interface Test {}
    final public class Test {}
    protected abstract class Test {}
    protected interface Test {}
    abstract public class Test {}

Accepted Answer

Question 8

Which of the following is/are legal method declarations?

    protected abstract void m1();
    static final void m1(){}
    synchronized public final void m1() {}
    private native void m1();

Accepted Answer

Question 9

class A 
{  
    protected int method1(int a, int b) 
    {
        return 0; 
    } 
}

Which is valid in a class that extends class A?

Accepted Answer

Question 10

Which of the following class level (nonlocal) variable declarations will not compile?

Accepted Answer