Certified Java Programmer Mock Exam

Question 1

Suppose that an interface, I1, is not a member of an enclosing class or interface. Which of the following modifiers can be applied to interface I1?

a. abstract
b. final
c. private
d. protected
e. public

Question 2

A class can not be called "tightly encapsulated" unless which of the following is true?

a. The class is a nested class.
b. The constructors are declared private.
c. The mutator methods are declared private.
d. The class implements the Encapsulated interface.
e. None of the above

Question 3

Suppose that an interface, I1, is not a member of an enclosing class or interface. Which of the following modifiers can be applied to interface I1?

a. abstract
b. public
c. static
d. synchronized
e. transient
f. volatile

Question 4

A class can not be called "tightly encapsulated" unless which of the following is true?

a. All member fields are declared final.
b. The class is not anonymous.
c. The internal data model can be read and modified only through accessor and mutator methods.
d. The class is an inner class.
e. None of the above

Question 5

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

a. abstract
b. const
c. final
d. private
e. protected
f. public

Question 6

class GFC500 {private String name;}
class GFC501 {
  private String name;
  private void setName(String name) {this.name = name;}
  private String getName() {return name;}
}
class GFC502 {
  private String name;
  public void setName(String name) {this.name = name;}
  public String getName() {return name;}
}

Which class is not tightly encapsulated?

a. GFC501
b. GFC502
c. GFC503
d. None of the above

Question 7

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

a. static
b. synchronized
c. transient
d. volatile
e. None of the above.

Question 8

class GFC505 extends GFC504 {
  public void setName(String name) {this.name = name;}
  public String getName() {return name;}
}
class GFC504 extends GFC503 {
  private void setName(String name) {this.name = name;}
  private String getName() {return name;}
}
class GFC503 {String name;}

Which class is tightly encapsulated?

a. GFC503
b. GFC504
c. GFC505
d. None of the above

Question 9

Which of the following modifiers can be applied to a class that is declared within an enclosing interface?

a. public
b. protected
c. private
d. abstract
e. static
f. final

Question 10

class GFC506 {private String name;}
class GFC507 extends GFC506 {
  String name;
  public void setName(String name) {this.name = name;}
  public String getName() {return name;}
}
class GFC508 extends GFC506 {
  private String name;
  public GFC508(String name) {setName(name);}
  public void setName(String name) {this.name = name;}
  public String getName() {return name;}
}

Which class is not tightly encapsulated?

a. GFC506
b. GFC507
c. GFC508
d. None of the above

Question 11

interface A {
  int a = 1;                        // 1
  public int b = 2;                 // 2
  public static int c = 3;          // 3
  public static final int d = 4;    // 4
}

Which field declaration results in a compile-time error?

a. 1
b. 2
c. 3
d. 4
e. None of the above

Question 12

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?

a. Compile-time error at line 1
b. Compile-time error at line 2
c. Compile-time error at line 3
d. Compile-time error at line 4
e. Compile-time error at line 5
f. Compile-time error at line 6
g. None of the above

Question 13

interface A {  
  protected int e = 5;              // 1
  private int f = 6;                // 2
  volatile int g = 7;               // 3
  transient int h = 8;              // 4
  public static final int d = 9;    // 5
}

Which of the field declarations does not result in a compile-time error?

a. 1
b. 2
c. 3
d. 4
e. 5
f. None of the above

Question 14

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?

a. Prints: main,B.m1
b. Compile-time error
c. Run-time error
d. None of the above

Question 15

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?

a. Prints: U, i1=1, i2=2
b. Prints: T, i1=1, i2=2
c. Prints: U, i1=null, i2=null
d. Prints: T, i1=null, i2=null
e. Run-time error
f. Compile-time error
g. None of the above

Question 16

class A {void m1(A a) {System.out.print("A");}}
class B extends A {void m1(B b) {System.out.print("B");}}
class C extends B {void m1(C c) {System.out.print("C");}}
class D {
  public static void main(String[] args) {
    A a1 = new A(); B b1 = new B();
    C c1 = new C(); A c2 = new C();
    c2.m1(a1); c2.m1(b1); c2.m1(c1);
}}

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

a. Prints: AAA
b. Prints: ABC
c. Prints: CCC
d. Compile-time error
e. Run-time error
f. None of the above

Question 17


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?

a. Prints: ABCI
b. Run-time error
c. Compile-time error
d. None of the above

Question 18

class A {void m1(A a) {System.out.print("A");}}
class B extends A {void m1(B b) {System.out.print("B");}}
class C extends B {void m1(C c) {System.out.print("C");}}
class D {
  public static void main(String[] args) {
    A a1 = new A(); B b1 = new A();
    C c1 = new A(); C c2 = new C();
    c2.m1(a1); c2.m1(b1); c2.m1(c1);
}}

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

a. Prints: AAA
b. Prints: ABC
c. Prints: CCC
d. Compile-time error
e. Run-time error
f. None of the above

Question 19


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?

a. Prints: DD
b. Prints: DE
c. Prints: ED
d. Prints: EE
e. Run-time error
f. Compile-time error
g. None of the above

Question 20

class A {void m1(A a) {System.out.print("A");}}
class B extends A {void m1(B b) {System.out.print("B");}}
class C extends B {void m1(C c) {System.out.print("C");}}
class D {
  public static void main(String[] args) {
    A a1 = new A(); B b1 = new B();
    C c1 = new C(); C c2 = new A();
    c2.m1(a1); c2.m1(b1); c2.m1(c1);
  }
}

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

a. Prints: AAA
b. Prints: ABC
c. Prints: CCC
d. Compile-time error
e. Run-time error
f. None of the above

Question 21

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?

a. Prints: AAA
b. Prints: ABC
c. Prints: CBA
d. Prints: CCC
e. Compile-time error
f. Run-time error
g. None of the above

Question 22


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?

a. Prints: AAA
b. Prints: ABC
c. Prints: CBA
d. Prints: CCC
e. Compile-time error
f. Run-time error
g. None of the above
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