Dan Chisholm's
Java Programmer Certification Mock Exam

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Question 1

Which of the following are true statements?

Question 2

Which of the following methods are static members of the Thread class?

Question 3

class SRC103 {
  public static void main (String[] args) {
    int i1 = Math.round(0.5f);
    int i2 = Math.round(1.5f);
    System.out.print(i1 + "," + i2);
}}

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

Question 4

class B {
  public static void main (String args[]) {
    Byte b1 = new Byte(1);    // 1
    Byte b2 = new Byte('2');  // 2 
    Byte b3 = new Byte("3");  // 3
    byte i1 = b1.byteValue()+b2.byteValue()+b3.byteValue(); // 4
    System.out.print(i1);
}}

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

Question 5

class A {
  public static void main (String args[]) {
    int primitiveInt = 1;
    long primitiveLong = 1L;
    float primitiveFloat = 1.0f;
    String s = "1";
    Integer i1 = new Integer(primitiveInt);
    Integer i2 = new Integer(primitiveLong);
    Integer i3 = new Integer(primitiveFloat);
    Integer i4 = new Integer(s);
    int i5 = i1.intValue() + i2.intValue() +
             i3.intValue() + i4.intValue();
    System.out.print(i5);
}}

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

Question 6

class B {
  public static void main (String args[]) {
    Long i1 = new Long(1);
    Long i2 = new Long(i1);
    System.out.print((i1==i2) + "," + i1.equals(i2));
}}

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

Question 7

class A {
  public static void main (String args[]) {
    Double d1 = new Double(1.0);
    Double d2 = new Double(d1);
    System.out.print(d1.equals(d2));
}}

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

Question 8

class B {
  public static void main(String[] args) {
    Boolean b1 = new Boolean(true);
    Boolean b2 = new Boolean(true);
    Boolean b3 = new Boolean("TrUe");
    Boolean b4 = new Boolean("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 9

class F {
  public static void main (String[] args) {
    Float f1 = new Float('B' - 'A');  // 1
    Float f2 = new Float(010);        // 2
    Float f3 = new Float(0x10);       // 3                     
    Float f4 = new Float(.1e1);       // 4
    Float f5 = new Float(1.0);        // 5
    Float f6 = new Float(1.0d);       // 6
    System.out.print(f1+","+f2+","+f3+","+f4+","+f5+","+f6);
}}

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

Question 10

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

Question 11

Which of these classes provides the specified features?

Question 12

import java.util.*;
class GFC101 {
  public static void main (String args[]) {
    Object a1 = new HashMap(), b1 = new ArrayList();
    Object c1 = new HashSet();
    System.out.print((a1 instanceof Collection)+",");
    System.out.print((b1 instanceof Collection)+",");
    System.out.print(c1 instanceof Collection);
}}

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

Question 13

If two instances of a class type are equal according to the equals method, then the same integer value must be returned by the hashCode method of the two objects.

Question 14

class MWC103 {
  public static void main(String[] args) {
    int[] a1 = {1,2,3};
    int []a2 = {4,5,6};
    int a3[] = {7,8,9};
    System.out.print(a1[1]+","+a2[1]+","+a3[1]);
}}

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

Question 15

Which of the following statements are true?

Question 16

Which of the following is used to prevent the serialization of a non-static field?

Question 17

Which of the following modifiers can not be used with the abstract modifier in a method declaration?

Question 18

class JSC203 {
  static int m1(byte b) {return b;}   // 1
  static int m2(char c) {return c;}   // 2
  static int m3(long l) {return l;}   // 3
  public static void main(String[] args) {
    byte b = 1; char c = '\u0002'; long l = 4L;
    System.out.print(""+m1(b)+m2(c)+m3(l));
}}

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

Question 19

public class A {int i1; void m1() {}}

Which of the following statements are true?

Question 20

Which of the following are class modifiers? Select all that are applicable to a top-level class and all that are applicable to a nested class. It is not required that a modifier be applicable to both.

Question 21

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?

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 {
      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 A {}  class B extends A {}  class C extends B {}
class D {
  void m1(A a) {System.out.print("A");}
  void m1(B b) {System.out.print("B");}
  void m1(C c) {System.out.print("C");}
  public static void main(String[] args) {
    A c1 = new C(); B c2 = new C(); C c3 = new C(); D d1 = new D();
    d1.m1(c1); d1.m1(c2); d1.m1(c3);
}}

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

Question 24

class MWC102 {
  public static void main (String[] args) {
    String s1 = "ABCDE";
    System.out.print(s1.substring(1,2)+s1.substring(3));
}}

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

Question 25

class MWC201 {
  public static void main (String[] args) {
    String s1 = new String("ABC"), s2 = new String("ABC");
    StringBuffer sb1 = new StringBuffer(s1);
    StringBuffer sb2 = new StringBuffer(s2);
    System.out.print(s1.equals(s2) + "," + sb1.equals(sb2));
}}

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

Question 26

class MWC203 {
  public static void main(String[] args) {
    int[] a1[] = {new int[]{1,2},new int[]{3,4,5}};
    int []a2[] = new int[][]{{1,2},{3,4,5}};
    int a3[][] = {{1,2},new int[]{3,4,5}};
    System.out.print(a1[0][1]+","+a2[1][0]+","+a3[1][2]);
}}

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

Question 27

Which statements are true?

Question 28

void m1() {
  Q q1 = null;
  for (int i = 0; i < 10; i++) {
    q1 = new Q();   // 1
    m2(q1);         // 2
  }
  System.out.print("All done"); // 3
}

When the processing of line 3 begins, how many objects of type Q that were created at line 1 have become eligible for garbage collection?

Question 29

abstract class A {
  private int x = 1, y = 1;
  public A(int x, int y) {this.x = x; this.y = y;}
  public abstract int math();
}
class B {
  static A a1 = new A(2,1) {public int math() {return x + y;}};
  static A a2 = new A(2,1) {public int math() {return x - y;}};
  static A a3 = new A(2,1) {public int math() {return x * y;}};
  static A a4 = new A(2,1) {public int math() {return x / y;}};
  public static void main(String[] args) {
    System.out.print("" + a1.math() + a2.math() +
                          a3.math() + a4.math());
}}

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