Certified Java Programmer Mock Exam

Question 1

class A {
  public static void main (String[] args) {
    Error error = new Error();
    Exception exception = new Exception();
    System.out.print((exception instanceof Throwable) + ",");
    System.out.print(error instanceof Throwable);
}}

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

a. Prints: false,false
b. Prints: false,true
c. Prints: true,false
d. Prints: true,true
e. Compile-time error
f. Run-time error
g. None of the above

Question 2

class A {A() throws Exception {}} // 1
class B extends A {B() throws Exception {}} // 2
class C extends A {C() {}} // 3

Which of the following statements are true?

a. class A extends Object.
b. Compile-time error at 1.
c. Compile-time error at 2.
d. Compile-time error at 3.

Question 3

class JMM102 {
  public static void main(String args[]) {
    for (int i = 0; i<5 ;i++) {
      switch(i) {
        case 0: System.out.print("v ");break;
        case 1: System.out.print("w ");
        case 2: System.out.print("x ");break;
        case 3: System.out.print("y ");
        case 4: System.out.print("z ");break;
        default: System.out.print("d ");
}}}}

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

a. Prints: v w x y z
b. Prints: v w x y z d
c. Prints: v w x x y z z
d. Prints: v w w x y y z d
e. Prints: d d d d d d
f. Run-time error
g. Compile-time error
h. None of the above

Question 4

class A {
  public static void main (String[] args) {
    Object error = new Error();
    Object runtimeException = new RuntimeException();
    System.out.print((error instanceof Exception) + ",");
    System.out.print(runtimeException instanceof Exception);
}}

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

a. Prints: false,false
b. Prints: false,true
c. Prints: true,false
d. Prints: true,true
e. Compile-time error
f. Run-time error
g. None of the above

Question 5

class JMM103 {
  public static void main(String args[]) {
    for (int i = 0; i < 5 ;i++) {
      switch(i) {
        0: System.out.print("v ");break;
        1: System.out.print("w ");
        2: System.out.print("x ");break;
        3: System.out.print("y ");
        4: System.out.print("z ");break;
}}}}

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

a. Prints: v w x y z
b. Prints: v w x x y z z
c. Prints: v w w x y y z
d. Run-time error.
e. Compile-time error.
f. None of the above.

Question 6

class Level1Exception extends Exception {}
class Level2Exception extends Level1Exception {}
class Level3Exception extends Level2Exception {}
class Purple {
  public static void main(String args[]) {
    int a,b,c,d,f,g,x;
    a = b = c = d = f = g = 0;
    x = 1;
    try {
      try {
        switch (x) {
          case 1: throw new Level1Exception();
          case 2: throw new Level2Exception();
          case 3: throw new Level3Exception();
      } a++; }
      catch (Level2Exception e) {b++;}
      finally {c++;}
    }
    catch (Level1Exception e) { d++;}
    catch (Exception e) {f++;}
    finally {g++;}
    System.out.print(a+","+b+","+c+","+d+","+f+","+g);
}}

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

a. Prints: 0,0,0,1,0,0
b. Prints: 0,0,1,1,0,1
c. Prints: 0,1,1,1,0,1
d. Prints: 1,0,1,1,0,1
e. Prints: 1,1,1,1,0,1
f. Compile-time error
g. Run-time error
h. None of the above

Question 7

class Level1Exception extends Exception {}
class Level2Exception extends Level1Exception {}
class Level3Exception extends Level2Exception {}
class Purple {
  public static void main(String args[]) {
    int a,b,c,d,f,g,x;
    a = b = c = d = f = g = 0;
    x = 2;
    try {
      try {
        switch (x) {
          case 1: throw new Level1Exception();
          case 2: throw new Level2Exception();
          case 3: throw new Level3Exception();
      } a++; }
      catch (Level2Exception e) {b++;}
      finally {c++;}
    }
    catch (Level1Exception e) { d++;}
    catch (Exception e) {f++;}
    finally {g++;}
    System.out.print(a+","+b+","+c+","+d+","+f+","+g);
}}

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

a. Prints: 0,0,1,0,0,1
b. Prints: 0,1,0,0,0,0
c. Prints: 0,1,1,0,0,1
d. Prints: 0,1,0,0,0,1
e. Prints: 1,1,1,0,0,1
f. Compile-time error
g. Run-time error
h. None of the above

Question 8

class Level1Exception extends Exception {}
class Level2Exception extends Level1Exception {}
class Level3Exception extends Level2Exception {}
class Purple {
  public static void main(String args[]) {
    int a,b,c,d,f,g,x;
    a = b = c = d = f = g = 0;
    x = 3;
    try {
      try {
        switch (x) {
          case 1: throw new Level1Exception();
          case 2: throw new Level2Exception();
          case 3: throw new Level3Exception();
      } a++; }
      catch (Level2Exception e) {b++;}
      finally {c++;}
    }
    catch (Level1Exception e) { d++;}
    catch (Exception e) {f++;}
    finally {g++;}
    System.out.print(a+","+b+","+c+","+d+","+f+","+g);
}}

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

a. Prints: 1,1,1,0,0,1
b. Prints: 0,1,1,0,0,1
c. Prints: 0,1,0,0,0,0
d. Prints: 0,1,0,0,0,1
e. Prints: 0,0,1,0,0,1
f. Compile-time error
g. Run-time error
h. None of the above

Question 9

class Level1Exception extends Exception {}
class Level2Exception extends Level1Exception {}
class Level3Exception extends Level2Exception {}
class Purple {
  public static void main(String args[]) {
    int a,b,c,d,f,g,x;
    a = b = c = d = f = g = 0;
    x = 4;
    try {
      try {
	switch (x) {
          case 1: throw new Level1Exception();
          case 2: throw new Level2Exception();
          case 3: throw new Level3Exception();
          case 4: throw new Exception();
      } a++; }
      catch (Level2Exception e) {b++;}
      finally{c++;}
    }
    catch (Level1Exception e) { d++;}
    catch (Exception e) {f++;}
    finally {g++;}
    System.out.print(a+","+b+","+c+","+d+","+f+","+g);
}}

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

a. Prints: 0,0,0,0,0,1
b. Prints: 0,0,0,0,1,0
c. Prints: 0,0,1,0,0,1
d. Prints: 0,0,1,0,1,1
e. Prints: 0,1,1,1,1,1
f. Prints: 1,1,1,1,1,1
g. Compile-time error
h. Run-time error
i. None of the above

Question 10

class Level1Exception extends Exception {}
class Level2Exception extends Level1Exception {}
class Level3Exception extends Level2Exception {}
class Purple {
  public static void main(String args[]) {
    int a,b,c,d,f,g,x;
    a = b = c = d = f = g = 0;
    x = 5;
    try {
      try {
	switch (x) {
          case 1: throw new Level1Exception();
          case 2: throw new Level2Exception();
          case 3: throw new Level3Exception();
          case 4: throw new Exception();
      } a++; }
      catch (Level2Exception e) {b++;}
      finally {c++;}
    }
    catch (Level1Exception e) { d++;}
    catch (Exception e) {f++;}
    finally {g++;}
    System.out.print(a+","+b+","+c+","+d+","+f+","+g);
}}

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

a. Prints: 1,0,0,0,0,0
b. Prints: 1,0,1,0,0,1
c. Prints: 0,0,1,0,0,1
d. Prints: 1,1,1,1,1,1
e. Compile-time error
f. Run-time error
g. None of the above

Question 11

class A {
  void m1(int i) {
    int j = i % 3;
    switch (j) {
      case 0: System.out.print("0"); break;
      case 1: System.out.print("1"); break;
      default:
        assert j == 2;
        System.out.print(j);
  }}
  public static void main (String[] args) {
    A a = new A();
    for (int i=5; i >= -1; i--) {a.m1(i);}
}}

Which statements are true?

a. With assertions enabled it prints 210210-1 followed by an AssertionError message.
b. With assertions enabled it prints 210210 followed by an AssertionError message.
c. With assertions enabled it prints only 210210.
d. With assertions enabled it prints nothing.
e. With assertions disabled it prints 210210-1
f. With assertions disabled it prints only 210210
g. Assertions should not be used within the default case of a switch statement.

Question 12

class B {
  private static int x1;
  public void setX(int x) {x1 = x;}
  public int getX() {return x1;}
  public static void main(String[] args) {
    int i1 = 0, j1 = 0;
    do {
      System.out.print(j1++);
      assert (i1 = j1 + x1) < 6;
    } while (i1 < 3);
}}

Assuming that the setX method is never invoked, which statements are true?

a. With assertions enabled it prints 012345 followed by an AssertionError message.
b. With assertions enabled it prints 012.
c. With assertions disabled it prints: 012345
d. With assertions disabled it prints: 012
e. With assertions disabled it attempts to print an infinite sequence of numbers.
f. With assertions disabled the variable i1 is incremented with each pass through the loop.
g. As a rule, the boolean expression of an assert statement should not be used to perform actions that are required for normal operation of the program.

Question 13

Which statements are true?

a. Assertions should not be used to validate arguments passed to public methods.
b. Assertions should not be used to validate arguments passed to nonpublic methods.
c. Assertions should not be used within the default case of a switch statement.
d. Assertions should not be used to perform processing that is required for the normal operation of the application.

Question 14

Which statements are true?

a. Assertions should never be placed at any point in the code that should not be reached under normal circumstances.
b. The compiler will generate an error if an assert statement is "unreachable" as defined by the Java Language Specification.
c. A catch clause should not be used to catch an AssertionError.
d. AssertionError is a checked exception.

Question 15

class JMM103 {
  public static void main(String args[]) {
    byte b = -1;
    switch(b) {
      case 0:    System.out.print("zero "); break;
      case 100:  System.out.print("100 ");  break;
      case 1000: System.out.print("1000 "); break;
      default: System.out.print("Default ");
}}}

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

a. Prints: zero
b. Prints: 100
c. Prints: 1000
d. Prints: Default
e. Run-time error
f. Compile-time error
g. None of the above

Question 16

class C {
  String m1(int i) {
    switch (i) {
      case 0: return "A";
      case 1: return "B";
      case 2: return "C";
      default: throw new AssertionError();
  }}
  public static void main(String[] args) {
    C c = new C();
    for (int i = 0; i < 4; i++) {
      System.out.print(c.m1(i));
}}}

Which statements are true?

a. With assertions enabled it prints ABC followed by an AssertionError message.
b. With assertions disabled it prints ABC followed by an AssertionError message.
c. Assertions should not be used within the default case of a switch statement.
d. In this code example an assert statement could not be used in place of the "throw" statement.

Question 17

class JMM104 {
  public static void main (String args[]) {
    char c = 'b';
    switch(c) {
      case 'a': System.out.print("1");
      case 'b': System.out.print("2");
      case 'c': System.out.print("3");
      default:  System.out.print("4");
}}}

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

a. Prints: 3
b. Prints: 34
c. Prints: 234
d. Prints: 1234
e. Run-time error
f. Compile-time error
g. None of the above

Question 18

class C {
  String m1(int i) {
    switch (i) {
      case 0: return "A";
      case 1: return "B";
      case 2: return "C";
      default:
        assert false;
    }
    return "E";
  }
  public static void main(String[] args) {
    C c = new C();
    for (int i = 0; i < 4; i++) {
      System.out.print(c.m1(i));
}}}

Which statements are true?

a. With assertions enabled it prints ABC followed by an AssertionError message.
b. With assertions enabled it prints ABCE followed by an AssertionError message.
c. With assertions disabled it prints ABC
d. With assertions disabled it prints ABCE
e. Assertions should not be used within the default case of a switch statement.

Question 19

class JMM105 {
  public static void main(String args[]) {
    int x = 6; int success = 0;
    do  {
      switch(x) {
        case 0: System.out.print("0"); x += 5; break;
        case 1: System.out.print("1"); x += 3; break;
        case 2: System.out.print("2"); x += 1; break;
        case 3: System.out.print("3"); success++; break;
        case 4: System.out.print("4"); x -= 1; break;
        case 5: System.out.print("5"); x -= 4; break;
        case 6: System.out.print("6"); x -= 5; break;
      }
    } while ((x != 3) || (success < 2));
}}

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

a. Prints: 60514233
b. Prints: 6152433
c. Prints: 61433
d. Prints: 6143
e. Run-time error
f. Compile-time error

Question 20

class C {
  String m1(int i) {
    switch (i) {
      case 0: return "A";
      case 1: return "B";
      case 2: return "C";
      default:
        assert false;
    }
  }
  public static void main(String[] args) {
    C c = new C();
    for (int i = 0; i < 4; i++) {
      System.out.print(c.m1(i));
}}}

Which statements are true?

a. With assertions enabled it prints ABC followed by an AssertionError message.
b. With assertions disabled it prints ABC followed by an AssertionError message.
c. Assertions should not be used within the default case of a switch statement.
d. In this code example a throw statement must be used in place of the assert statement.
e. Compile-time error

Question 21

class JMM106 {
  public static void main(String args[]) {
    int x = -5; int success = 0;
    do  {
      switch(x) {
        case 0: System.out.print("0"); x += 5; break;
        case 1: System.out.print("1"); x += 3; break;
        case 2: System.out.print("2"); x += 1; break;
        case 3: System.out.print("3"); success++; break;
        case 4: System.out.print("4"); x -= 1; break;
        case 5: System.out.print("5"); x -= 4; break;
        case 6: System.out.print("6"); x -= 5; break;
        default: x += x < 0 ? 2 : -2;
      }
    } while ((x != 3) || (success < 2));
}}

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

a. Prints: 60514233
b. Prints: 1433
c. Prints: 61433
d. Prints: 051433
e. Run-time error
f. Compile-time error

Question 22


class JMM101 {
  public static void main(String[] args) {
    int i = 0;
    while (i++ < args.length) {
      System.out.print(args[i]);
}}}
java JMM101 A B C D E F

What is the result of attempting to compile and run the program using the specified command line?

a. Prints: JMM101ABCDEF
b. Prints: ABCDEF
c. Compile-time error
d. Run-time error
e. None of the above
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