Checkers Code Fails to Work for Jumps

[boe john]

I have attempted to code checkers for a school project, but I am unable to code a method for multiple jumps. In my current version, I have attempted to find the possible moves in a one piece radius, add those moves to an ArrayList known as mainList, and use recursion to find all possible moves. Afterward, for each possible final destination piece, the program adds the pieces that need to be reset to "NO" to an ArrayList known as sublist, which is one of the attributes of each piece. However, my jumps do not work.

I have attempted to debug why my program is not removing the correct pieces, and in the image with a trial run posted below, the underlined "RP" with coordinates of (4,3) is not reset, and instead, the program thinks that the piece with coordinates of (3,2) should be reset. Apparently, the program is trying to reset the final destination piece rather than the middle piece. What am I missing that is causing it to do this?

Note: Some of the code has been removed to fit character count.

	
	public static void playerTurn(piece[][] grid, boolean black)
	{
		Scanner input=new Scanner (System.in);
		ArrayList<piece> mainList=new ArrayList<piece>();
		piece placeholder1=null;
		piece placeholder2=null;
		piece placeholder3=null;
		piece placeholder4=null;
		int x1, y1, x4, y4;
		String x2, x3, y2, y3, x5;
		if (black==true)
		{
			x1=1;
			y1=-1; 
			x4=2;
			y4=-2;
			x2="BP";
			x3="BK";
			y2="RP";
			y3="RK";
			x5="Black: ";
		}
		else
		{
			x1=-1;
			y1=1;
			x4=-2;
			y4=2;
			x2="RP";
			x3="RK";
			y2="BP";
			y3="BK";
			x5="Red: ";
		}	
		printGrid(grid);
		System.out.println(x5+"insert the x-coordinate of the piece you would like to move (left being 0).");
		int a=input.nextInt();
		input.nextLine();
		System.out.println(x5+"insert the y-coordinate of the piece you would like to move (top being 0).");
		int b=input.nextInt();
		input.nextLine();
		System.out.println(x5+"input the x-coordinate of the position to which you would like to move the piece (left being 0).");
		int c=input.nextInt();
		input.nextLine();
		System.out.println(x5+"input the y-coordinate of the position to which you would like to move the piece (top being 0).");
		int d=input.nextInt();
		input.nextLine();
		if (a<0 || a>7 || b<0 || b>7 || c<0 || c>7 || d<0 || d>7)
		{
			System.out.println("That move is out of bounds. Please replay your move.\n");
			playerTurn(grid, black);
			return;
		}
		else if (grid[b][a].toString().equals("NO") || grid[b][a].toString().equals(y2) || grid[b][a].toString().equals(y3))
		{
			invalidMove(grid, black);
			return;
		}
		moveCheck(grid, black, mainList, b, a);
		for (int i=0; i<mainList.size(); i++)
		{
			if (mainList.get(i).getXPosition()==c && mainList.get(i).getYPosition()==d)
			{
				System.out.println(mainList.get(i).getSubList().size());
				for (int j=0; j<mainList.get(i).getSubList().size(); j++)
				{
					System.out.println(mainList.get(i).getSubList().get(j).getXPosition());
					System.out.println(mainList.get(i).getSubList().get(j).getYPosition());
					grid[mainList.get(i).getSubList().get(j).getYPosition()][mainList.get(i).getSubList().get(j).getXPosition()]=new piece(mainList.get(i).getSubList().get(j).getYPosition(), mainList.get(i).getSubList().get(j).getXPosition());
				}
				grid[d][c]=grid[b][a];
				grid[b][a]=new piece(b,a);
			} 
			else
			{
				invalidMove(grid, black);
				return;
			}
		}
	}
	public static void moveCheck(piece[][] grid, boolean black, ArrayList<piece> mainList, int b, int a)
	{
		int x1, y1, x4, y4;
		String y2, y3;
		if (black==true)
		{
			x1=1;
			y1=-1; 
			x4=2;
			y4=-2;
			y2="RP";
			y3="RK";
		}
		else
		{
			x1=-1;
			y1=1;
			x4=-2;
			y4=2;
			y2="BP";
			y3="BK";
		}
		if ((b>1 && a<6 && black==true) || (b<6 && a>1 && black==false))
		{
			if ((grid[b + y1][a + x1].toString().equals(y2) || grid[b + y1][a + x1].toString().equals(y3)) && grid[b+y4][a+x4].toString().equals("NO"))
			{
				grid[b+y4][a+x4].getSubList().add(grid[b+y1][a+x1]);
				if (grid[b][a].getSubList().size()!=0)
					grid[b+y4][a+x4].getSubList().addAll(grid[b][a].getSubList());
				mainList.add(grid[b+y4][a+x4]);
				moveCheck(grid, black, mainList, b+y4, a+x4);
			}
		}
		if ((b>1 && a>1 && black==true) || (b<6 && a<6 && black==false))
		{
			if ((grid[b + y1][a + y1].toString().equals(y2) || grid[b + y1][a + y1].toString().equals(y3)) && grid[b+y4][a+y4].toString().equals("NO"))
			{
				grid[b+y4][a+y4].getSubList().add(grid[b+y1][a+y1]);
				if (grid[b][a].getSubList().size()!=0)
					grid[b+y4][a+y4].getSubList().addAll(grid[b][a].getSubList());
				mainList.add(grid[b+y4][a+y4]);
				moveCheck(grid, black, mainList, b+y4, a+y4);
			}
		}
	}
}

[boe john]

I resolved the issue with the pieces not resetting, but my multi jump still does not work.

[Knute Snortum]

Welcome to the Ranch, boe john!

Debugging a class with variable names like x1, y2, etc. is very difficult for the author and nearly impossible for anyone else!  If you're using an IDE, use its Rename function and slowly name variable something that is describes their function.  x5 might be renamed pieceColorPrompt, for instance.

I know this doesn't solve your problem directly, but you will find that this process makes debugging much easier.

Some other tips:

Don't write if (something == true), just write if (something)

Class names should begin with an uppercase letter

Don't call a method recursively when you don't need recursion (example: line 52)