Dan Chisholm's
Java Programmer Certification Mock Exam

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Question 1

class A {
  public static void main(String[] args) {
    char a = 'a', b = 'b'; // 'a' = 97, 'b' = 98
    System.out.print(a + b + "" + a + b);
}}

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

Question 2

class Black {
  public static void main(String[] args) {
    short s1 = 1;        //1
    char c1 = 1;         //2
    byte b1 = s1;        //3
    byte b2 = c1;        //4
    final short s2 = 1;  //5
    final char c2 = 1;   //6
    byte b3 = s2;        //7
    byte b4 = c2;        //8
}}

Compile-time errors are generated at which lines?

Question 3

class Magenta {
  static byte a = (byte)127, b = (byte)128, c = (byte)255, d = (byte)256;
  public static void main(String args[]) {
    System.out.print(a + " " + b + " " + c + " " + d);
}}

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

Question 4

interface I1 {}  interface I2 {}
class Base implements I1 {}
class Sub extends Base implements I2 {}
class Red {
  public static void main(String args[]) {
    Sub s1 = new Sub();
    I2 i2 = s1;          // 1
    I1 i1 = s1;          // 2
    Base base = s1;      // 3
    Sub s2 = (Sub)base;  // 4
}}

A compile-time error is generated at which line?

Question 5

class Green {
  public static void main (String args[]) {
    int[] i = null;  // 1
    Cloneable c = i; // 2
    i = (int [])c;   // 3
}}

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

Question 6

class Primitives {
  static void printFloat(float f) {System.out.println(f);}
  static void printDouble(double d) {System.out.println(d);}
  public static void main(String[] args) {
    byte b = 1;     // 1
    short s = b;    // 2
    char c = s;     // 3
    int i = c;      // 4
    long l = i;     // 5
    float f = l;    // 6
    printFloat(i);  // 7
    printFloat(l);  // 8
    printDouble(l); // 9
}}

A compile-time error is generated at which line?

Question 7

interface I1 {}  interface I2 {}
class Base implements I1 {}
class Sub extends Base implements I2 {}
class Orange {
  public static void main(String args[]) {
    Base base = new Base();
    I1 i1 = base;           // 1
    Sub sub = (Sub)base;    // 2
}}

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

Question 8

class Purple {
  public static void main (String []args) {
    int[] i = {1,2,3};  // 1
    Object obj = i;     // 2
    i = obj;            // 3
}}

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

Question 9

class Maroon {
  public static void main (String[] args) {
    int a = 1;    // 1
    short b = 1;  // 2
    long c = 1;   // 3
    a = c + a;    // 4
    c = b + a;    // 5
}}

A compile-time error is generated at which line?

Question 10

interface I1 {}  interface I2 {}
class Base implements I1 {}
class Sub extends Base implements I2 {}
class Yellow {
  public static void main(String args[]) {
    Base base = new Sub();  // 1
    I1 i1 = base;           // 2
    Sub sub = (Sub)base;    // 3
    I2 i2 = (Sub)base;      // 4
}}

A compile-time error is generated at which line?

Question 11

import java.io.Serializable;
class Blue {
  public static void main (String args[]) {
    int[] i = {1,2,3};   // 1
    Serializable s = i;  // 2
    i = (int [])s;       // 3
}}

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

Question 12

class Teal {
  public static void main (String[] args) {
    byte b = 1;    // 1
    long l = 1000; // 2
    b += l;        // 3
}}

A compile-time error is generated at which line?

Question 13

interface I1 {}  interface I2 {}
class Base implements I1 {}
class Sub extends Base implements I2 {}
class Gray {
  public static void main(String []args) {
  Base[] base = {new Base()};  // 1
  Sub sub[] = {new Sub()};     // 2
  Object obj = sub;            // 3
  base = obj;                  // 4
}}

A compile-time error is generated at which line?

Question 14

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

A compile-time error is generated at which line?

Question 15

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 program?

Question 16

interface I1 {}  interface I2 {}
class Base implements I1 {}
class Sub extends Base implements I2 {}
class Silver {
  public static void main(String []args) {
    Base[] base = {new Base()};
    Sub sub[] = new Sub[1];    // 1
    Object obj = base;         // 2
    sub = (Sub[])obj;          // 3
    I1 []i1 = (I1[])obj;       // 4
}}

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

Question 17

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

A compile-time error is generated at which line?

Question 18

class UltraViolet {
  public static void main (String[] args) {
    char a = '\u002a', b = '\u0024'; // a = Asterisk *; b = Dollar Sign $
    System.out.print(a + b);           // 1
    System.out.print(" ABC" + a + b);  // 2
}}

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

Question 19

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

A compile-time error is generated at which line?