Certified Java Programmer Mock Exam

Question 1

Which of the following are modifiers that can be applied to a method declaration within an interface?

Question 2

Which of the following are modifiers that can be applied to a field declaration within an interface?

Question 3

Which of the following are modifiers that can be applied to an interface that is not a member of an enclosing class?

Question 4

interface A {
  void m1();              // 1
  public void m2();       // 2
  protected void m3();    // 3
  private void m4();      // 4
  abstract void m5();     // 5
}

Compile-time errors are generated at which lines?

Question 5

interface A {void main(String[] args);}               // 1
interface B {public void main(String[] args);}        // 2
interface C {public static void main(String[] args);} // 3
interface D {protected void main(String[] args);}     // 4
interface E {private void main(String[] args);}       // 5

Which interface declarations generate a compile-time error?

Question 6

interface I {String s1 = "I";}
class A implements I {String s1 = "A";}
class B extends A {String s1 = "B";}
class C extends B {
  String s1 = "C";
  void printIt() {
    System.out.print(((A)this).s1 + ((B)this).s1 +
                     ((C)this).s1 + ((I)this).s1);
  }
  public static void main (String[] args) {
    new C().printIt();
  }
}

What is the result of attempting to compile and run the above program?

Question 7

1.  interface I10 {
2.    String name = "I10";
3.    String s10 = "I10.s10";
4.  }
5.  interface I20 {
6.    String name = "I20";
7.    String s20 = "I20.s20";
8.  }
9.  class C10 implements I10, I20 {
10.   public static void main(String[] args) {
11.     System.out.print(s10+",");
12.     System.out.print(s20+",");
13.     System.out.print(name);
14.   }
15. }

What is the result of attempting to compile and run the above program?

Question 8

class A {}
class B extends A {}
class C extends B {
  static void m(A x, A y) {System.out.print("AA");}
  static void m(A x, B y) {System.out.print("AB");}
  static void m(B x, A y) {System.out.print("BA");}
  static void m(B x, B y) {System.out.print("BB");}
  static void m(A x, C y) {System.out.print("AC");}
  public static void main(String[] args) {
    C c = new C();
    m(c, c);
  }
}

What is the result of attempting to compile and run the above program?

Question 9

class A {}
class B extends A {}
class C extends B {
  static void m1(A x) {System.out.print("m1A");}
  static void m2(B x) {System.out.print("m2B"); m1(x);}
  static void m2(A x) {System.out.print("m2A"); m1(x);}
  static void m3(C x) {System.out.print("m3C"); m2(x);}
  static void m3(B x) {System.out.print("m3B"); m2(x);}
  static void m3(A x) {System.out.print("m3A"); m2(x);}
  public static void main(String[] args) {
    m3(new C());
  }
}

What is the result of attempting to compile the program?

Question 10

class M {
  static String s1 = "M.s1";
  static void printS1(){System.out.print("M.printS1,"+s1+" ");}
  M() { printS1();}
}

class N extends M {
  static String s1 = "N.s1";
  static void printS1(){System.out.print("N.printS1,"+s1+" ");}
  N() { printS1();}
  public static void main(String[] args) {
    N n = new N();
  }
}

What is the result of attempting to compile and run the above program?

Question 11

class A {}
class B extends A {}
class C {
  void m(A x) {System.out.print("A");}
  void m(B x) {System.out.print("B");}
  public static void main(String[] args) {
    C c = new C();
    c.m(null);
  }
}

What is the result of attempting to compile and run the above program?

Question 12

abstract class D {
  String s1 = "D";
  abstract String getS1();
}
class E extends D {
  String s1 = "E";
  String getS1() {return s1;}
}
class F {
  public static void main (String[] s) {
    D x = new E();
    System.out.print(x.s1 + x.getS1());
  }
}

What is the result of attempting to compile and run the above program?

Question 13

class G {
  String s1 = "G.s1";
  void printS1(){System.out.print("G.printS1," + s1);}
  G() { printS1();}
}

class H extends G {
  String s1 = "H.s1";
  void printS1(){System.out.print("H.printS1," + s1);}
  public static void main(String[] args) {
    H h = new H();
  }
}

What is the result of attempting to compile and run the above program?

Question 14

class C {
  void printS1() {System.out.print("C.printS1 ");}
  static void printS2() {System.out.print("C.printS2 ");}
}

class D extends C {
  void printS1(){System.out.print("D.printS1 ");}
  void printS2() {System.out.print("D.printS2 ");}
  public static void main (String args[]) {
    C c = new D();
    c.printS1(); c.printS2();
  }
}

What is the result of attempting to compile and run the above program?

Question 15

class A {void m1() {System.out.print("A");}}
class B extends A {void m1(){System.out.print("B");}}
class C extends B {void m1() {System.out.print("C");}}
class D extends C {
  void m1() {System.out.print("D");}
  void m2() {
    m1();
    ((C)this).m1(); // 1
    ((B)this).m1(); // 2
    ((A)this).m1(); // 3
  }
  public static void main (String[] args) {
    new D().m2(); // 4
  }
}

What is the result of attempting to compile and run the above program?

Question 16

interface A {
  String m1();
  class B implements A {public String m1() {return "B";}}
}
class E {
  public static void main(String[] args) {
    // Insert statement here.
  }
}

Which of the following statements could be inserted into the program to print the String ""B"?

Question 17

class A {String s1="A";}
class B extends A {String s1="B";}
class C extends B {String s1="C";}
class D extends C {
  String s1="D";
  void m1() {
    System.out.print(s1  + ",");
    System.out.print(((C)this).s1  + ","); // 1
    System.out.print(((B)this).s1  + ","); // 2
    System.out.print(((A)this).s1); // 3
  }
  public static void main (String[] args) {
    new D().m1(); // 4
  }
}

What is the result of attempting to compile and run the above program?