public void FillArray() {     for (int i = 1; i &lt; numEmp; i++)     {         employees[i] = true;     } }   I think this part may be the reason I'm getting the NullPointerException error, but I don't know what I'm missing. I have put my full code for the program below just in case there is something that is wrong with that that is giving me that error message.  //client class  public class Downsize {     public static void main (String [] args)     {         System.out.print("Do you want to downsize the company? (Y/N): ");         String dummy = APIO.getString().toUpperCase();                 while (dummy.equals("Y"))         {             Employee employee = new Employee();             System.out.print("Do you want to downsize the company? (Y/N):              dummy = APIO.getString().toUpperCase();         }     } }     //object class   public class Employee     {         int numEmp;         int sprayer;         int winner;         boolean [] employees;          public Employee()         {             System.out.print("How many employees? (0 to end): ");             int numEmp = APIO.getInt();             System.out.print("Who gets the spray can first?: ");             int sprayer = APIO.getInt();             FillArray();             Selection();             Winner();         }          public void FillArray()         {             for (int i = 1; i &lt; numEmp; i++)             {                 employees[i] = true;             }         }          public void Selection()         {                     System.out.println("EM="); //debugging method             for (boolean em: employees)             {                 System.out.println(em);             }              int complete = numEmp;             while (complete &gt; 1)             {                 System.out.print("spraycan passed to #" + sprayer);                 if ((sprayer + 1) &gt; numEmp)                 {                     sprayer = 0;                 }                 while (employees[sprayer + 1] == false)                 {                     sprayer++;                     if (sprayer &gt;= numEmp)                     {                         sprayer = 0;                     }                 }                 employees[sprayer + 1] = false;                 System.out.print("  -  sprays #" + (sprayer + 1) + "'s hair");                 complete--;                 sprayer++;                 while (employees[sprayer] == false)                 {                     sprayer++;                     if (sprayer &gt; numEmp)                     {                         sprayer = 1;                     }                 }             }         }          public void Winner()         {             if (sprayer == 0)             {                 sprayer = 1;                 System.out.print("\nThe Winner is #" + sprayer);                 System.out.print("\n");             }         }     }   //stack trace for the error message  java.lang.NullPointerException     at Employee.FillArray(Employee.java:22)     at Employee.&lt;init&gt;(Employee.java:14)     at Downsize.main(Downsize.java:9)
What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?
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