Certified Java Programmer Mock Exam

Question 1

class MCZ21 {
  public static void main (String[] args) {
    // Insert code here.
}}

Which of the following lines can be inserted at the specified location without generating a compile-time error?

Question 2

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

Compile-time errors are generated at which lines?

Question 3

class MWC112 {
  static void m1(String s1) {
    s1 = s1.toUpperCase(); System.out.print(s1);
  }
  static void m2(String s1) {
    s1.toLowerCase(); System.out.print(s1);
  }
  public static void main(String[] s) {
    String s1 = "Ab";
    m1(s1); m2(s1);
    System.out.print(s1);
}}

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

Question 4

class SRC115 {
  static String m(int i) {return "int";}
  static String m(long i) {return "long";}
  static String m(float i) {return "float";}
  static String m(double i) {return "double";}
  public static void main (String[] args) {
    long seed = 1L;
    System.out.print(m(Math.random(seed)));
}}

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

Question 5

import java.util.*;
class GFC112 {
  public static void main (String[] args) {
    Object m = new LinkedHashSet();
    System.out.print((m instanceof Collection)+",");
    System.out.print((m instanceof Set)+",");
    System.out.print(m instanceof List);
}}

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

Question 6

class MWC212 {
  public static void main(String[] args) {
    int[] a1[],a2[];  // 1
    int []a3,[]a4;    // 2
    int []a5,a6[];    // 3
    int[] a7,a8[];    // 4
}}

A compile-time error is generated at which line?

Question 7

abstract class A {                   // 1
  abstract synchronized void m1();   // 2
  abstract synchronized class B {}   // 3
  synchronized class C extends B {}  // 4
}

Which line does not result in a compile-time error?

Question 8

class ColorException extends Exception {}
class WhiteException extends ColorException {}
abstract class Color {
  abstract void m1() throws ColorException;
}
class White extends Color {
  void m1() throws WhiteException {throw new WhiteException();}
  public static void main (String[] args) {
    White white = new White();
    int a,b,c; a = b = c = 0;
    try {white.m1(); a++;} 
      catch (WhiteException e) {b++;}
      finally {c++;}
    System.out.print(a+","+b+","+c);
}}

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

Question 9

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

Question 10

class MWC113 {
  public static void main(String[] s) {
    String s1 = "1", s2 = "2", s3 = s1 + s2;
    s1 += s2; s3 += s1;
    System.out.println(s3);
}}

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

Question 11

class SRC116 {
  static String m(int i) {return "int";}
  static String m(long i) {return "long";}
  static String m(float i) {return "float";}
  static String m(double i) {return "double";}
  public static void main (String[] args) {
    System.out.print(m(Math.sin(0.0f))+",");
    System.out.print(m(Math.cos(0.0f))+",");
    System.out.print(m(Math.tan(0.0f)));
}}

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

Question 12

import java.util.*;
class GFC113 {
  public static void main (String[] args) {
    Object m = new LinkedHashSet();
    System.out.print((m instanceof Collection)+",");
    System.out.print((m instanceof Set)+",");
    System.out.print(m instanceof HashSet);
}}

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

Question 13

Which of the following are command-line switches used to enable assertions in non-system classes?

Question 14

class MCZ22 {
  public static void main (String[] args) {
    // Insert code here.
}}

Which of the following lines will generate a compile-time error if inserted at the specified location?

Question 15

class A {
  private static int counter;
  public static int getCounter(){return counter++;}
  private static int innerCounter;
  public static int getInnerCounter(){return innerCounter++;}
  private String name;
  A() {name = "A" + getCounter();}
  class B {
    private String name;
    B() {
      name = "B" + getInnerCounter();
      System.out.print(A.this.name + name);
  }}
  void m1() {new A().new B();}  // 1
  void m2() {new A.B();}        // 2
  void m3() {new B();}          // 3
  public static void main(String[] args) {
    A a1 = new A();
    a1.m1(); a1.m2(); a1.m3();
}}

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

Question 16

Which of the following will not force a thread to move into the Not-Runnable state?

Question 17

Which of these classes provides the specified features?

Question 18

class C {
  int a, b, c;
  public void setA(int i) {a = i; assert validateC() : c;}
  public void setB(int i) {b = i; assert validateC() : c;}
  private boolean validateC() {
    return c > a + 2 * b;
  }
  public int m1(int i) {
    c = a + b + i;
    assert validateC() : c;
    return c;
  }
  public C(int i) {
    c = i; assert validateC() : c;
  }
  public static void main(String[] args) {
    C c = new C(251); c.setA(50); c.setB(100);
}}

Which statements are true?

Question 19

class A {
  private static int counter;
  public static int getCounter(){return counter++;}
  private static int innerCounter;
  public static int getInnerCounter(){return innerCounter++;}
  private String name;
  A() {name = "A" + getCounter();}
  class B {
    private String name;
    B() {
      name = "B" + getInnerCounter();
      System.out.print(A.this.name + name); // 1
  }}
  static void m1() {new A().new B();}  // 2
  static void m2() {this.new B();}     // 3
  static void m3() {new B();}          // 4
  public static void main(String[] args) {
    m1(); m2(); m3();
}}

What are the results of attempting to compile and run the program?

Question 20

Which of the following will cause a dead thread to restart?

Question 21

Which of these classes provides the specified features?

Question 22

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 {
      throw new Level1Exception();
      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?

Question 23

class JMM113 {
  public static void main (String[] args) {
    int i = 0, j = 0, k = 0;
    do while (i++ < 3)
      System.out.print(k++);
    while (j++ < 3);
}}

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

Question 24

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 25

class JMM114 {
  public static void main (String[] args) {
    int i = 0, j = 0;
    while (i++ < 3) do
      System.out.print(j);
    while (j++ < 3);
}}

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

Question 26

class EBH023 {
  static String m1(boolean b){return b?"T":"F";}
  public static void main(String [] args) {
    boolean b1 = false?false:true?false:true?false:true;
    boolean b2 = false?false:(true?false:(true?false:true));
    boolean b3 = ((false?false:true)?false:true)?false:true;
    System.out.println(m1(b1) + m1(b2) + m1(b3));
}}

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

Question 27

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 28

class EBH021 {
  public static void main(String[] args) {
    System.out.print((-1 & 0x1f) + "," + (8 << -1));
}}

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