Singly Linked List Java implementation

[xayto]

Ok for a Uni assignment I am being requested to construct a Polynomial Class with various methods. I get the general jist of what I need to accomplish but I am having trouble with one method.

What I am having trouble with is where I need to add a new node to the Start of a linked list, I am not able to using the code below. I only get the original value of the polynomial Returned.

Any prods in the right direction would be great!

	public static Polynomial add(Polynomial polynomial, double coefficient, int power)
	{
		//Check validity of Polynomial 
		if (polynomial == null) return null;
		if (Math.abs(coefficient) < epsilon) coefficient = 0.0;
		if (coefficient == 0.0) return null;
		if (power < 0) return null;
		
		//If power is less than smallest node add as last node (works)
		if (power < polynomial.powerMin())
		  {
			Polynomial newNode = new Polynomial(coefficient,power);
			if (polynomial.successor != null)
			{
				while (polynomial.successor != null)
				{
					polynomial.successor = polynomial.successor.successor;
				}
				polynomial.successor = newNode;
			}
			
			else if (polynomial.successor == null )
				polynomial.successor = newNode;
			
		  }
		
		//if power is greater than the first node add to the front (Doesn't work)
		else if (power > polynomial.powerMax())
			if (polynomial == null)
			{
				Polynomial newNode = new Polynomial(coefficient,power);
				polynomial = newNode;
			}
			else{
		{
			Polynomial newNode = new Polynomial(coefficient,power);
			newNode.successor = polynomial;
			polynomial = newNode;
			return polynomial;
			
		}
			}
		//where power is the same in both nodes, add coefficients and leave power alone (works)
		else
		{
		 if (power == polynomial.power) 
			 polynomial.coefficient = polynomial.coefficient + coefficient;
			 		 
		}
		return polynomial;
		
	}

[Norm]

I need to add a new node to the Start of a linked list,

When adding to the beginning of a linked list, how do you set the list's pointer to include the new node?

I only get the original value of the polynomial Returned.

What is your method supposed to return?