Certified Java Programmer Mock Exam

Question 1

Which of the following statements are true?

Question 2

Suppose that the superclass constructor invocation, "super(argumentListopt);", appears explicitly in a subclass constructor. If a compile-time error is to be avoided then the arguments for the superclass constructor invocation, "super(argumentListopt);", can not refer to which of the following?

Question 3

class A {void m1(String s1) {}}
class B extends A {
  void m1(String s1) {}  // 1
  void m1(boolean b) {}  // 2
  void m1(byte b) throws Exception {}  // 3
  String m1(short s) {return new String();} //4
  private void m1(char c) {} // 5
  protected void m1(int i) {} // 6
}

What is the result of attempting to compile the program?

Question 4

class A {
  void m1() {System.out.print("A.m1");}
}
class B extends A {
  void m1() {System.out.print("B.m1");}
  static void m1(String s) {System.out.print(s+",");}
}
class C {
  public static void main (String[] args) {
    B.m1("main"); new B().m1();
}}

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

Question 5

Which of the following are true statements?

Question 6

class A {
  String s1 = "A.s1"; String s2 = "A.s2";
}
class B extends A {
  String s1 = "B.s1";
  public static void main(String args[]) {
    B x = new B(); A y = (A)x;
    System.out.println(x.s1+" "+x.s2+" "+y.s1+" "+y.s2);
}}

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

Question 7

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 program?

Question 8

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

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

Question 9

class P {
  static void printS1(){System.out.print("P.printS1 ");}
  void printS2() {System.out.print("P.printS2 ");}
  void printS1S2(){printS1();printS2();}
}
class Q extends P {
  static void printS1(){System.out.print("Q.printS1 ");}
  void printS2(){System.out.print("Q.printS2 ");}
  public static void main(String[] args) {
    new Q().printS1S2();
}}

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

Question 10

class R {
  private void printS1(){System.out.print("R.printS1 ");}
  protected void printS2() {System.out.print("R.printS2 ");}
  protected void printS1S2(){printS1();printS2();}
}
class S extends R {
  private void printS1(){System.out.print("S.printS1 ");}
  protected void printS2(){System.out.print("S.printS2 ");}
  public static void main(String[] args) {
    new S().printS1S2();
}}

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

Question 11

class T {
  private int i1, i2;
  void printI1I2() {System.out.print("T, i1="+i1+", i2="+i2);}
  T(int i1, int i2) {
    this.i1=i1; this.i2=i2;
}}
class U extends T {
  private int i1, i2;
  void printI1I2() {System.out.print("U, i1="+i1+", i2="+i2);}
  U(int i1, int i2) {this.i1=i1; this.i2=i2;}
  public static void main(String[] args) {
    T t = new U(1,2); t.printI1I2();
}}

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

Question 12

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 program?

Question 13

abstract class D {
  String s1 = "D"; String getS1() {return s1;}
}
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 program?

Question 14

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

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

Question 15

class A {String s1 = "A";}
class B extends A {String s1 = "B";}
class C extends B {String s1 = "C";}
class D {
  static void m1(A x) {System.out.print(x.s1);}
  static void m1(B x) {System.out.print(x.s1);}
  static void m1(C x) {System.out.print(x.s1);}
  public static void main(String[] args) {
    A a; B b; C c; a = b = c = new C();
    m1(a); m1(b); m1(c);
}}

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

Question 16

class Leg{}
class Fur{}
abstract class Pet {
  public abstract void eat();
  public abstract void sleep();
}
class Dog extends Pet {
  Leg leftFront = new Leg(), rightFront = new Leg();
  Leg leftRear = new Leg(), rightRear = new Leg();
  Fur fur = new Fur();
  public Fur shed() {return fur;}
  public void eat() {}
  public void sleep() {}
}
class Cat extends Dog {
  public void ignoreOwner() {}
  public void climbTree() {}
}

Which of the following statements is not a true statement?

Question 17

class A {
  A() {System.out.print("CA ");}
  static {System.out.print("SA ");}
}
class B extends A {
  B() {System.out.print("CB ");}
  static {System.out.print("SB ");}
  public static void main (String[] args) {
    B b = new B();
}}

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

Question 18

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(this.s1  + ",");      // 1
    System.out.print(((C)this).s1  + ","); // 2
    System.out.print(((B)this).s1  + ","); // 3
    System.out.print(((A)this).s1);        // 4
  }
  public static void main (String[] args) {
    new D().m1(); // 5
}}

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

Question 19

class SuperA {String s1="SuperA";}
class SuperB {String s1="SuperB";}
class A extends SuperA {
  String s1="A";
  class B extends SuperB {  // 1
    String s1="B";
    void m1() {
      System.out.print(this.s1 + ",");   // 2
      System.out.print(super.s1 + ",");  // 3
      System.out.print(A.this.s1 + ","); // 4
      System.out.print(A.super.s1);      // 5
    }
  }
  public static void main (String[] args) {
    new A().new B().m1();  // 6
}}

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

Question 20

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 program?

Question 21

class A {public void m1() {System.out.print("A1");}}
class B extends A {
  public void m1() {System.out.print("B1");}
  public void m2() {System.out.print("B2");}
}
class C {
  public static void main(String[] args) {
    A a1 = new B();
    a1.m1();      // 1
    a1.m2();      // 2
   ((B)a1).m1();  // 3
   ((B)a1).m2();  // 4
}}

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