Certified Java Programmer Mock Exam

Question 1

class Red {
  public int a;
  public static int b;
  public static void main (String[] in) {
    Red r1 = new Red();
    Red r2 = new Red();
    r1.a++;
    r1.b++;
    System.out.print(r1.a+", "+r1.b+", "+r2.a+", "+r2.b);
  }
}

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

Question 2

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

Assuming these class definitions are contained in a file named Basics.java, what is the result of attempting to compile the contents of the file?

Question 3

1.  class Basics1 {}
2.  class Basics2 {}
3.  class Basics3 {}
4.  class Basics4 {}

Assuming these class definitions are contained in a file named Basics.java, what is the result of attempting to compile the contents of the file?

Question 4

class A {
  public static void main (String[] args) {
    private int x = 1;
    protected int y = 2;
    public int z = 3;
    System.out.println(x+y+z);
  }
}

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

Question 5

Which of the following modifiers can be applied to a method?

Question 6

Which of the following statements are true?

Question 7

class E {
  public static void main (String[] args) {
    byte[] a = new byte[1];
    long[] b = new long[1];
    float[] c = new float[1];
    Object[] d = new Object[1];
    System.out.print(a[0]+","+b[0]+","+c[0]+","+d[0]);
  }
}

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

Question 8

abstract class A {}
final class B {}
private class C {}
protected class D {}
static class E {}
synchronized class F {}
transient class G {}
volatile class H {}
strictfp class I {}

Suppose these are top-level class declarations and not nested class declarations. Which of these results in a compiler error?

Question 9

Class A is declared in a file named A.java.
1.  package com.dan.chisholm;
2.  
3.  public class A {
4.    public void m1() {System.out.print("A.m1, ");}
5.    protected void m2() {System.out.print("A.m2, ");}
6.    private void m3() {System.out.print("A.m3, ");}
7.    void m4() {System.out.print("A.m4, ");}
8.  }

Class D is declared in a file named D.java.
9.  package com.dan.chisholm.other;
10.  
11. import com.dan.chisholm.A;
12.  
13. public class D {
14.   public static void main(String[] args) {
15.     A a = new A();
16.  	a.m1();
17.  	a.m2();
18. 	a.m3();
19. 	a.m4();
20.   }
21. }

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

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

class A {
  public float a;        // 1
  protected float b;     // 2
  strictfp float h;      // 3
  private float c;       // 4
  static float d;        // 5
  synchronized float i;  // 6
}

Compile-time errors are generated at which lines?

Question 12

Which of the following modifiers can be applied to a field?

Question 13

Suppose that the superclass constructor invocation statement, super, appears explicitly in a subclass constructor. If a compile-time error is to be avoided then the arguments for the superclass constructor invocation statement, super, can not refer to which of the following?

Question 14

Which of the following statements are true?

Question 15

Which of the following statements are true?

Question 16

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

Compile-time errors occur at which lines?

Question 17

class A {
  public static void main(String[] args) {
    int[][] a = {{1,2,3},{4,5,6},{7,8,9,10}};
    System.out.print(a[0][2]+","+a[1][0]+","+a[2][1]);
  }
}

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

Question 18

class A {public String toString() {return "A";}}
class B {
  public static void main(String[] arg) {
    A[]     a1 = new A[1];         // 1
    A[][]   a2 = new A[2][];       // 2
    A[][][] a3 = new A[3][][];     // 3
    a1[0] = new A();               // 4
    a2[0] = a2[1] = a1;            // 5
    a3[0] = a3[1] = a3[2] = a2;    // 6
    System.out.print(a3[2][1][0]); // 7
  }
}

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