Certified Java Programmer Mock Exam

Question 1

public class Basics {}      // 1
class Basics1 {}            // 2
protected class Basics2 {}  // 3
private class Basics3 {}    // 4
Class Basics4 {}            // 5

Suppose these are top-level class declarations and not nested class declarations; and suppose that all of the declarations are contained in one file named Basics.java. Compile-time errors are generated at which lines?

Question 2

class MCZ29 {
  public static void main (String[] args) {
    char a = '\a';  // 1 
    char b = '\b';  // 2
    char c = '\f';  // 3
    char d = '\n';  // 4
    char e = '\r';  // 5  
}}

A compile-time error is generated at which line?

Question 3

class C {
  public static void main(String[] args) {
    Boolean b1 = Boolean.valueOf(true);
    Boolean b2 = Boolean.valueOf(true);
    Boolean b3 = Boolean.valueOf("TrUe");
    Boolean b4 = Boolean.valueOf("tRuE");
    System.out.print((b1==b2) + ",");
    System.out.print((b1.booleanValue()==b2.booleanValue()) + ",");
    System.out.println(b3.equals(b4));
}}

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

Question 4

Which of the instance creation expressions produce a run-time error?

Question 5

Which of the following class instance creation expressions would generate a run-time error?

Question 6

Which interface of the java.util package offers the specified behavior?

Question 7

import java.util.*;
class GFC102 {
  public static void main (String args[]) {
    Object a = new HashSet();
    System.out.print((a instanceof Set)+",");
    System.out.print(a instanceof SortedSet);
}}

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

Question 8

If two instances of a class type are not equal according to the equals method, then the same integer value must not be returned by the hashCode method of the two objects.

Question 9

class MWC104 {
  public static void main(String[] args) {
    int[5] a1;  // 1
    int []a2;   // 2
    int[   ]a3; // 3
    int a4[];   // 4
}}

A compile-time error is generated at which line?

Question 10

Suppose that the compiler generates a default constructor for a class. If a compile-time error is to be avoided, which of the following must be true?

Question 11

Which of the following statements are true?

Question 12

Which of the following statements is true?

Question 13

class JSC204 {
  static int m1(short s)  {return s;}   // 1
  static int m2(float f) {return f;}    // 2
  public static void main(String[] args) {
    short s = 3; float f = 5.0f;
    System.out.print(""+m1(s)+m2(f));
}}

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

Question 14

Which of the following modifiers can be applied to a member class?

Question 15

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?

Question 16

Which of the following are modifiers that can be applied to an interface that is a member of a directly enclosing class?

Question 17

class JJF4 {
  public static void main(String args[]) {
    System.out.print(Long.toHexString(Byte.MAX_VALUE)+",");
    System.out.print(Long.toHexString(Character.MAX_VALUE)+",");
    System.out.print(Long.toHexString(Short.MAX_VALUE));
}}

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

Question 18

class MWC204 {
  public static void main(String[] args) {
    int[][] a1 = {{1,2},{3,4,5},{6,7,8,9},{}};
    System.out.print(a1.length);
}}

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

Question 19

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?

Question 20

Which statements are true?

Question 21

class Q {
  private int id;
  public void finalize() {System.out.print(id);}
  public Q(int i) {id = i;}
}
class R {
  public static void main(String[] args) {
    Q q1 = null;
    for (int i = 0; i < 10; i++) {
      q1 = new Q(i); // 1
    }
    System.gc();     // 2
}}

When the processing of line 2 begins, how many objects of type Q that were created at line 1 are eligible for garbage collection?

Question 22

class GFM14 {
  static byte a; static short b; static char c;
  static int d; static long e; static String s;
  public static void main(String[] args) {
    System.out.println(a+","+b+","+(int)c+","+d+","+e+","+s);
}}

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

Question 23

class EBH005 {
  public static void main (String[] s) {
    byte b = 127; b <<= 2;
    System.out.println(b);
}}

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

Question 24

class Teal {
  public static void main (String[] args) {
    byte b = 1;    // 1
    long l = 1000; // 2
    b += l;        // 3
}}

A compile-time error is generated at which line?

Question 25

interface I1 {}
interface I2 {}
class Base implements I1 {}
class Sub extends Base implements I2 {}
class Gray {
  public static void main(String []args) {
  Base[] base = {new Base()};  // 1
  Sub sub[] = {new Sub()};     // 2
  Object obj = sub;            // 3
  base = obj;                  // 4
}}

A compile-time error is generated at which line?

Question 26

abstract class A {
  private int x = 4;
  private int y = 2;
  public int x() {return x;}
  public void x(int x) {this.x = x;}
  public int y() {return y;}
  public void y(int y) {this.y = y;}
}
interface B {int math();}
class C {
  static class D extends A implements B {
    public int math() {return x()+y();}
  }
  static A a1 = new A() implements B {
    public int math() {return x()+y();}
  };
  public static void main(String[] args) {
    System.out.print(new C.D().math());
    System.out.print(a1.math());
}}

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

Question 27

Which of these lists contains at least one word that is not a Java keyword?

Question 28

class EBH204 {
  static boolean m1(String s, boolean b) {
    System.out.print(s + (b ? "T" : "F"));
    return b;
  }
  public static void main(String[] args) {
    m1("A",m1("B",false) || m1("C",true) || m1("D",false));
}}

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

Question 29

class EBH104 {
  static int m(int i) {
    System.out.print(i + ", ");
    return i;
  }

  public static void main(String s[]) {
    int i = 1;
    m(m(++i) - m(i++) + m(-i) * m(~i));
}}

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