Thread: Unending Loop Issue? Can't find it.

Although I think this is an issue with my loops structure/conditions this could also be an issue with how Java does arithmetic. I'm sure this is probably simple but I can't find it right now.
The polynomial object is composed of an array of size 100 which stores the coefficients of a polynomial in index locations corresponding to the power of each respective term. The purpose of this code is to create a new polynomial object which is the result of multiplying two polynomials.
I'm pretty sure that the loop is not ending but I'm not sure why. The initial S.o.ps of i+j values are what I expect but then they go into enormous negative numbers and I have no idea why.

  public Polynomial mult(Polynomial p)
                    throws ExponentOutOfRangeException
  {
      Polynomial multiPolynomial = new Polynomial();
 
 
      //Start testcode
      System.out.print("this polynomial ");
      this.displayPolynomial();
      System.out.print("p polynomial ");
      p.displayPolynomial();
      //End testcode
 
 
      for(int i = 0; i < 99; i++)
      {
          for(int j = 0; j < 99; i++)
          {
            if((i+j) < MAX)
            {
                multiPolynomial.polyArr[i + j] = multiPolynomial.polyArr[i + j] + (this.polyArr[i] * p.polyArr[j]);
            }
          }
      }
   // Multiplies polynomial p to this polynomial without modifying this
   // polynomial and returns the result.
   // Precondition: None.
   // Postcondition: The returned polynomial is the product of this 
   // and p.  Both this and p are unchanged.
   // Throws: ExponentOutOfRangeException if exponent is out of range.
      return multiPolynomial;
  }

By the way,

for(int j = 0; j < 99; i++)

You're incrementing i in the j loop, not j