Certified Java Programmer Mock Exam

Question 1

class A {
  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 above program?

Question 2

class A {
  public static void main(String[] args) {
    final short s1 = 1; // 1
    final char c1 = 1;  // 2
    byte b1 = s1;       // 3
    byte b2 = c1;       // 4
    byte b3 = 1;        // 5
    byte b4 = 1L;       // 6
    byte b5 = 1.0;      // 7
    byte b6 = 1.0d;     // 8
  }
}

What is the result of attempting to compile the program?

Question 3

class V {
  public static void main (String[] args) {
    float a = Float.POSITIVE_INFINITY;
    double b = Double.POSITIVE_INFINITY;
    double c = Double.NaN;
    System.out.print((a == b)+","+(c == c)+","+(c != c));
  }
}

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

Question 4

class V {
  public static void main (String[] args) {
    System.out.print(Float.POSITIVE_INFINITY % 2 + ",");
    System.out.print(Float.NEGATIVE_INFINITY % 2 + ",");
    System.out.print(2 % Float.NEGATIVE_INFINITY);
  }
}

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

Question 5

1.  interface I1 {}
2.  interface I2 {}
3.  class Base implements I1 {}
4.  class Sub extends Base implements I2 {}
5.  class Silver {
6.    public static void main(String []args) {
7.      Base[] base = {new Base()};
8.      Sub sub[] = new Sub[1];
9.      Object obj = base;
10.     sub = (Sub[])obj;
11.     I1 []i1 = (I1[])obj;
12.   }
13. }

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

Question 6

class Q {
  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?

Question 7

 1. interface I1 {}
 2. interface I2 {}
 3. class Base implements I1 {}
 4. class Sub extends Base implements I2 {}
 5.
 6. class Orange {
 7.   public static void main(String args[]) {
 8.     Base base = new Base();
 9.     I1 i1 = base;
10.     Sub sub = (Sub)base;
11.   }
12. }

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

Question 8

1. class Maroon {
2.   public static void main (String[] args) {
3.     int i=1;
4.     short s = 1;
5.     long l=1,m=2;
6.     i = l + i;
7.     l = s + i;
8.   }
9. }

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

Question 9

class Sienna {
  static double a;
  static float b;
  static int c;
  static char d;
  public static void main(String[] args) {

    a = b = c = d = 'a';
    System.out.println(a+b+c+d == 4 * 'a');
  }
}

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

Question 10

class A {}
class B extends A {}
class C extends B {
  static void m(A x, A y) {System.out.print("AA");}
  static void m(A x, B y) {System.out.print("AB");}
  static void m(B x, A y) {System.out.print("BA");}
  static void m(B x, B y) {System.out.print("BB");}
  public static void main(String[] args) {
    C c = new C();
    m(c, c);
  }
}

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

Question 11

class U {
  public static void main(String args[]) {
    int a = 1;
    a += ++a + a++;
    System.out.print(a);
  }
}

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

Question 12

class C {
  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?

Question 13

 1. interface I1 {}
 2. interface I2 {}
 3. class Base implements I1 {}
 4. class Sub extends Base implements I2 {}
 5. class Yellow {
 6.   public static void main(String args[]) {
 7.     Base base = new Sub();
 8.     I1 i1 = base;
 9.     Sub sub = (Sub)base;
10.     I2 i2 = (Sub)base;
11.   }
12. }

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

Question 14

class A {}
class B {
  static void m(Object x) {System.out.print("Object");}
  static void m(String x) {System.out.print("String");}
  public static void main(String[] args) {
    m(null);
  }
}

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

Question 15

1.  class White {
2.    public static void main(String args[]) {
3.      int[] i = {1,2,3,4,5};
4.      long[] l1 = new long[5];
5.      long []l2 = l1;
6.      long l3[] = (long[])i;
7.      long l4[] = new long[5];
8.      l4[1] = i[1];
9.    }
10. }

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

Question 16

1. class Black {
2.   public static void main(String args[]) {
3.     int[] i = {1,2,3,4,5};
4.     long[] l = new long[5];
5.     for (int j=0;j < l.length(); j++) {
6.       l[j] = i[j];
7.     }
8.   }
9. }

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

Question 17

class A {}
class B {
  static void m(Object x) {System.out.print("Object");}
  static void m(String x) {System.out.print("String");}
  static void m(A x) {System.out.print("A");}
  public static void main(String[] args) {
    m(null);
  }
}

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

Question 18

1.  class Amber {
2.    public static void main(String[] args) {
3.      int[][] a = {{1,2},{0,1,2},{-1,0,2}};
4.      Object[] obj = (Object[])a.clone();
5.      for(int i = 0;i<obj.length; i++) {
6.        int[] ia = (int[])obj[i];
7.        System.out.print(ia[i]);
8.      }
9.    }
10. }

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