Certified Java Programmer Mock Exam

Question 1

Which of these classes provides the specified features?

Question 2

import java.util.*;
class GFC106 {
  public static void main (String args[]) {
    Object a = new HashSet(), b = new HashMap();
    Object c = new Hashtable();
    System.out.print((a instanceof Map)+",");
    System.out.print((b instanceof Map)+",");
    System.out.print(c instanceof Map);
}}

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

Question 3

Which of the following classes override both the equals and hashCode methods?

Question 4

Which of these classes provides the specified features?

Question 5

import java.util.*;
class GFC107 {
  public static void main (String args[]) {
    Object a = new HashSet(), b = new HashMap();
    Object c = new Hashtable();
    System.out.print((a instanceof Cloneable)+",");
    System.out.print((b instanceof Cloneable)+",");
    System.out.print(c instanceof Cloneable);
}}

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

Question 6

class A {
  int i1, i2;
  public void setI1(int i) {i1 = i;}
  public int getI1() {return i1;}
  public void setI2(int i) {i2 = i;}
  public int getI2() {return i2;}
  public A(int ii1, int ii2) {i1 = ii1; i2 = ii2;}
  public boolean equals(Object obj) {
    if (obj instanceof A) {
      return (i1 == ((A)obj).getI1());
    }
    return false;
  }
  public int hashCode() {
    // Insert statement here.
}}

Which of the following statements could be inserted at the specified location without violating the hash code contract?

Question 7

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

Question 8

import java.util.*;
import java.io.Serializable;
class GFC108 {
  public static void main (String args[]) {
    HashMap a = new HashMap();
    boolean b1, b2, b3;
    b1 = (a instanceof Cloneable) & (a instanceof Serializable);
    b2 = a instanceof Map;
    b3 = a instanceof Collection;
    System.out.print(b1 + "," + b2 + "," + b3);
}}

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

Question 9

class A {
  int i1, i2;
  public void setI1(int i) {i1 = i;}
  public int getI1() {return i1;}
  public void setI2(int i) {i2 = i;}
  public int getI2() {return i2;}
  public A(int ii1, int ii2) {i1 = ii1; i2 = ii2;}
  public boolean equals(Object obj) {
    if (obj instanceof A) {
      return (i1 == ((A)obj).getI1()) & (i2 == ((A)obj).getI2());
    }
    return false;
  }
  public int hashCode() {
    // Insert statement here.
}}

If inserted at the specified location, which of the following statements would produce the most efficient hashCode method?

Question 10

Which of the following classes allow unsynchronized read operations by multiple threads?

Question 11

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

Question 12

import java.util.*;
class GFC110 {
  public static void main (String[] args) {
    Object m = new LinkedHashMap();
    System.out.print((m instanceof Collection)+",");
    System.out.print((m instanceof Map)+",");
    System.out.print(m instanceof List);
}}

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

Question 13

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

Question 14

import java.util.*;
class GFC111 {
  public static void main (String[] args) {
    Object m = new LinkedHashMap();
    System.out.print((m instanceof Collection)+",");
    System.out.print((m instanceof Map)+",");
    System.out.print(m instanceof HashMap);
}}

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

Question 15

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 16

import java.util.*;
class GFC109 {
  public static void main (String[] args) {
    Object v = new Vector();
    System.out.print((v instanceof Collections)+",");
    System.out.print((v instanceof Arrays)+",");
    System.out.print(v instanceof List);
}}

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

Question 17

Which of these classes provides the specified features?

Question 18

Which of these classes provides the specified features?