Thread: NullPointerException Error

Hi,

I keep receiving a NullPointerException and have been unable to find a way to resolve it. Any assistance would be much appreciated.

public class FitnessFrog extends Frog
{
   // instance variable
   private int totalDistanceSprinted;
   private Random randomNumber;
   public FitnessFrog sporty1;
   public FitnessFrog sporty2;
 
   // constructor
   /**
    * Constructor for objects of class FitnessFrog.
    */
   public FitnessFrog()
   {
      super();
      this.randomNumber = new Random();      
      this.totalDistanceSprinted = 0;
   }
 
   /**
    * Setter for totalDistanceSprinted.
    */
   private void setTotalDistanceSprinted(int aValue)
   {
      this.totalDistanceSprinted = aValue;
   }
 
   /**
    * Getter for totalDistanceSprinted.
    */
   public int getTotalDistanceSprinted()
   {
      return this.totalDistanceSprinted;
   }      
 
   /**
    * Sets the value of the totalDistanceSprinted variable to 0.
    * Returns no value.
    */
   public void resetTotalDistanceSprinted()
   {
      this.setTotalDistanceSprinted(0);
   }
 
   /**
    * Returns a random integer value specifying a sprint length 
    * between 2 and 5 inclusive.
    */
   private int getSprintLength()
   {
      return (this.randomNumber.nextInt(4) + 2);
   }   
 
   /**
    * Getter for sporty1.
    */
   public FitnessFrog getSporty1()
   {
      return this.sporty1;
   }  
 
   /**
    * Getter for sporty2.
    */
   public FitnessFrog getSporty2()
   {
      return this.sporty2;
   }   
 
   /**
    *     * 
    * Saves the colour of the receiver, then sets the colour of the
    * receiver to red and gets a sprint length. Next enters a loop 
    * and on each iteration does the following: First, checks if the 
    * receiver is on the last stone (numbered 11) in which case moves 
    * the receiver to the first stone (numbered 1), otherwise moves
    * the receiver right; then increments the total distance sprinted.
    * Upon exit from the loop, casues the receiver to jump once and
    * then resets its colour. Returns no value.
    */
   public void sprint()
   {
      //save colour of the receiver
       OUColour colour1 = this.getSporty1().getColour();
       OUColour colour2 = this.getSporty2().getColour();
 
      //Set colour of receiver to red & get sprint length
     this.setColour(OUColour.RED);
     this.getSprintLength();
 
     //
     if(this.position == 11)
     {
      this.home();
     } else this.right(); this.setTotalDistanceSprinted(this.getTotalDistanceSprinted()+ getSprintLength() + 1);
 
     // Reset receivers colour
      this.getSporty1().setColour(colour1);
      this.getSporty2().setColour(colour2);
   }
 }

Thanks,
Steven

I keep receiving a NullPointerException

Please copy the full text of the error message and paste it here.

Some problems I see:
multiple statements on one line
missing {}s for statement(s) following else

java.lang.NullPointerException
in FitnessFrog.sprint(FitnessFrog.java:95)

There is a null value at line 95 when it is executed. Look at line 95 and find the variable with the null value and then backtrack in the code to see why the variable is null.