Dan Chisholm's
Java Programmer Certification Mock Exam

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I would also like to read your response to the following questions.

Question 1

class EBH019 {
  public static void main (String args[]) {
    int i1 = 0xffffffff, i2 = i1 << 1;
    int i3 = i1 >> 1, i4 = i1 >>> 1;
    System.out.print(Integer.toHexString(i2) + ",");
    System.out.print(Integer.toHexString(i3) + ",");
    System.out.print(Integer.toHexString(i4));
}}

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

a. Prints: ffffffff,ffffffff,ffffffff
b. Prints: ffffffff,ffffffff,7fffffff
c. Prints: ffffffff,7fffffff,ffffffff
d. Prints: ffffffff,7ffffffe,7ffffffe
e. Prints: fffffffe,ffffffff,ffffffff
f. Prints: fffffffe,ffffffff,7fffffff
g. Prints: fffffffe,7fffffff,ffffffff
h. Prints: fffffffe,7fffffff,7fffffff
i. Run-time error
j. Compile-time error
k. None of the above

Question 2

class MCZ20 {
  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?

a. String a = 'a';
b. String b = 'abc';
c. String c = '\u0041';
d. String d = '\uabcd';
e. None of the above

Question 3

class G {
  public static void main (String[] args) {
    Integer i1 = new Integer("1"), i2 = new Integer("1");
    StringBuffer sb1 = new StringBuffer("1");
    StringBuffer sb2 = new StringBuffer("1");
    System.out.print(sb1.equals(sb2)+","+i1.equals(i2));
}}

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 4

 •Entries are organized as key/value pairs.
 •Duplicate entries replace old entries.
 •Entries are sorted using a Comparator or the Comparable interface.

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

a. List
b. Map
c. Set
d. SortedSet
e. SortedMap
f. None of the above

Question 5

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?

a. Prints: false,false,false
b. Prints: false,false,true
c. Prints: false,true,false
d. Prints: false,true,true
e. Prints: true,false,false
f. Prints: true,false,true
g. Prints: true,true,false
h. Prints: true,true,true
i. None of the above

Question 6

class MWC210 {
  public static void main(String[] args) {
    int[] a2 = {1,2}, a3 = {3,4,5}, a4 = {6,7,8,9}; // 1
    int[][] a1 = {a2,a3,a4};                        // 2
    System.out.print(a1[0][1]+","+a1[1][2]+","+a1[2][3]);
}}

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

a. Prints: 14
b. Prints: 16
c. Prints: 1,5,9
d. Prints: 2,4,8
e. Prints: 2,5,9
f. Compile-time error
g. Run-time error
h. None of the above

Question 7

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

Which line results in a compile-time error?

a. 1
b. 2
c. 3
d. 4
e. None of the above.

Question 8

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

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

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

Question 9

interface A {  
  protected int e = 5;              // 1
  private int f = 6;                // 2
  volatile int g = 7;               // 3
  transient int h = 8;              // 4
  public static final int d = 9;    // 5
}

Which of the field declarations does not result in a compile-time error?

a. 1
b. 2
c. 3
d. 4
e. 5
f. None of the above

Question 10

class MCZ19 {
  public static void main (String[] args) {
    String a1 = null;        // 1
    String b1 = 'null';      // 2
    String c1 = "null";      // 3
    String d1 = "'null'";    // 4
}}

A compile-time error is generated at which line?

a. 1
b. 2
c. 3
d. 4
e. None of the above

Question 11

class A {void m1() {System.out.print("A.m1");}}
class B extends A {
  void m1() {System.out.print("B.m1");}
  static void m1(String s) {System.out.print(s+",");}
}
class C {
  public static void main (String[] args) {B.m1("main"); new B().m1();}
}

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

a. Prints: main,B.m1
b. Compile-time error
c. Run-time error
d. None of the above

Question 12

class MWC111 {
  static void m1(String s1) {
    s1.replace('A','Y'); System.out.print(s1);
  }
  static void m2(String s1) {
    s1 = s1.replace('A','Z'); System.out.print(s1);
  }
  public static void main(String[] s) {
    String s1 = "A"; m1(s1); m2(s1);
    System.out.print(s1);
}}

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

a. Prints: AAA
b. Prints: YZA
c. Prints: YAA
d. Prints: AZA
e. Prints: AZZ
f. Compile-time error
g. Run-time error
h. None of the above

Question 13

class SRC114 {
  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.random()));
}}

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

a. Prints: int
b. Prints: long
c. Prints: float
d. Prints: double
e. Compile-time error
f. Run-time error
g. None of the above

Question 14

class H {
  public static void main (String[] args) {
    int i1, i2; Integer i3, i4;
    i1=new Integer(Integer.parseInt("1")).intValue();     // 1
    i3=new Integer(Integer.parseInt("1")).intValue();     // 2
    i2=Integer.parseInt(Integer.valueOf("1").toString()); // 3
    i4=Integer.parseInt(Integer.valueOf("1").intValue()); // 4
}}

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

a. Compile-time error at 1.
b. Compile-time error at 2.
c. Compile-time error at 3.
d. Compile-time error at 4.
e. Compile-time error
f. Run-time error

Question 15

 •Entries are not organized as key/value pairs.
 •Duplicate entries are rejected.
 •Entries are sorted using a Comparator or the Comparable interface.

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

a. List
b. Map
c. Set
d. SortedSet
e. SortedMap
f. None of the above

Question 16

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?

a. Prints: false,false,false
b. Prints: false,false,true
c. Prints: false,true,false
d. Prints: false,true,true
e. Prints: true,false,false
f. Prints: true,false,true
g. Prints: true,true,false
h. Prints: true,true,true
i. None of the above

Question 17

class MWC211 {
  public static void main(String[] args) {
    int a1[3];    // 1
    int []a2[];   // 2
    int[   ]a3;   // 3
    int[] a4[];   // 4
}}

A compile-time error is generated at which line?

a. 1
b. 2
c. 3
d. 4
e. None of the above

Question 18

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

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

a. 1
b. 2
c. 3
d. 4
e. None of the above

Question 19

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

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

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

Question 20

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

a. abstract
b. final
c. private
d. protected
e. public

Question 21

class EBH020 {
  public static void main (String[] args) {
    int a = 1 | 2 ^ 3 & 5;
    int b = ((1 | 2) ^ 3) & 5;
    int c = 1 | (2 ^ (3 & 5));
    System.out.print(a + "," + b + "," + c);
}}

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

a. Prints: 0,0,0
b. Prints: 0,0,3
c. Prints: 0,3,0
d. Prints: 0,3,3
e. Prints: 3,0,0
f. Prints: 3,0,3
g. Prints: 3,3,0
h. Prints: 3,3,3
i. Run-time error
j. Compile-time error
k. None of the above

Question 22

class A {
  private void m1 (int i) {
    assert i < 10 : i; System.out.print(i);
  }
  public void m2 (int i) {
    assert i < 10 : i; System.out.print(i);
  }
  public static void main (String[] args) {
    A a = new A(); a.m1(11); a.m2(12);
}}

Which statements are true?

a. If assertions are enabled at run time it prints an error message.
b. With assertions enabled it prints nothing.
c. With assertions disabled it prints an error message.
d. With assertions disabled it prints 1112.
e. With assertions disabled it prints nothing.
f. The assert statements are being used to check a precondition--something that must be true when the method is invoked.
g. Method m1 is an example of an improper use of an assert statement: an assert statement should not be used for argument checking in a non-public method.
h. Method m2 is an example of an improper use of an assert statement: an assert statement should not be used for argument checking in a public method.

Question 23

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
  }}
  void m1() {new A().new B();}  // 2
  void m2() {this.new B();}     // 3
  void m3() {new B();}          // 4
  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?

a. Prints: A0B0A1B1A1B2
b. Prints: A0B0A1B1A2B2
c. Prints: A1B0A0B1A0B2
d. Compile-time error at line 1
e. Compile-time error at line 2
f. Compile-time error at line 3
g. Compile-time error at line 4
h. Other compile-time error.
i. Run-time error
j. None of the above

Question 24

Which of the following are true statements?

a. The Thread.yield method might cause the thread to move to the Not-Runnable state
b. The Thread.yield method might cause the thread to move to the Ready state
c. The same thread might continue to run after calling the Thread.yield method
d. The Thread.yield method is a static method
e. The behavior of the Thread.yield method is consistent from one platform to the next
f. The Thread.sleep method causes the thread to move to the Not-Runnable state
g. The Thread.sleep method causes the thread to move to the Ready state

Question 25

class B {
  int a, b, c;
  private void setA(int i) {a = i;}
  private void setB(int i) {b = i;}
  private int m1 (int i) {
    c = a + b + i; assert c < 200 : c; return c;
  }
  public static void main (String[] args) {
    B b = new B(); b.setA(50); b.setB(100); b.m1(50);
}}

Which statements are true?

a. If assertions are not enabled at run time it prints an error message.
b. If assertions are not enabled at run time it prints nothing.
c. With assertions enabled it prints an error message.
d. With assertions enabled it prints nothing.
e. The assert statement is being used to check a postcondition--something that must be true when the method completes successfully.

Question 26

class JMM111 {
  public static void main (String[] args) {
    int j = 0;
    for (int i = 0; i < 2; i++) do
      System.out.print(i);
    while (j++ < 2);
}}

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

a. Prints: 0001
b. Prints: 012
c. Prints: 012012
d. Prints: 012345
e. Prints: 001122
f. Prints: 1112
g. Prints: 111222
h. Prints: 121212
i. Run-time error
j. Compile-time error
k. None of the above

Question 27

class JMM112 {
  public static void main (String[] args) {
    int j = 0;
    for (int i = 0; i++ < 2;) do
      System.out.print(i);
    while (j++ < 2);
}}

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

a. Prints: 0001
b. Prints: 012
c. Prints: 012012
d. Prints: 012345
e. Prints: 001122
f. Prints: 1112
g. Prints: 111222
h. Prints: 121212
i. Run-time error
j. Compile-time error
k. None of the above

Question 28


class A {String s1="A";}
class B extends A {String s1="B";}
class C extends B {String s1="C";}
class D extends C {
  String s1="D";
  void m1() {
    System.out.print(this.s1  + ",");      // 1
    System.out.print(((C)this).s1  + ","); // 2
    System.out.print(((B)this).s1  + ","); // 3
    System.out.print(((A)this).s1);        // 4
  }
  public static void main (String[] args) {
    new D().m1(); // 5
}}

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

a. Prints: D,D,D,D
b. Prints: D,C,B,A
c. Compile-time error at 1.
d. Compile-time error at 2.
e. Compile-time error at 3.
f. Compile-time error at 4.
g. Compile-time error at 5.
h. Run-time error
i. None of the above
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