很抱歉，标题措辞不好，但我不知道如何正确地总结这个问题。
我设计了一个棋盘位置的象棋游戏，棋子不知道自己的位置，只有国王例外，只要国王移动，他的位置就会被一个简单的设定器更新--
Gameflow.java

public static void movePiece(Player player, int pieceSelection, int action) {
        int x = pieceSelection / 10;
        int y = pieceSelection % 10;
        Board board = Board.boardConstructor(); //board is a Singleton
        Piece piece = Board.squares[x][y].getPiece();   
        ...
           if (piece.getType().equals(Type.KING)) {              
                King king = (King) piece;
                king.setXY(endX, endY);
                System.out.println("King moved to " + king.getX() + king.getY()); //prints old location
            }

King.java

public class King extends Piece {
    ...
    public void setXY(int x, int y) {        
        this.x = x;
        this.y = y;
        System.out.println("The King's location is now " + this.x + this.y); //prints new location
    }

www.example.com中setter内的printlnKing.java按预期输出，但国王的位置未在其他位置更新
我被迷惑了，为什么更新的位置没有被保存，但我仍然能够通过更改一行来修复这个问题-
Gameflow.java

public static void movePiece(Player player, int pieceSelection, int action) {
            if (piece.getType().equals(Type.KING)) {                
                King king = player.getKing(); // <-- changed how I select the King
                king.setXY(endX, endY);
                System.out.println("King moved to " + king.getX() + king.getY()); //prints correctly
            }

这是我的代码，它复制棋子，并通过播放器抓取国王
Player.java

private Player(String name, boolean isWhite) {
        this.name = name;
        this.isWhite = isWhite;
        if (isWhite) {
            team = createPieces(6);
        } else {
            team = createPieces(0);
        }
    }

    public static Piece[] createPieces(int start) {
        Piece[] team = new Piece[16];       
        int count = 0;
        int end = start + 2;
        for (int i = start; i < end; i++) {
            for (int j = 0; j < 8; j++) {
                team[count] = Board.squares[i][j].getPiece();
                count++;
            }
        }
        return team;
    }

    public King getKing() {
        Piece theKing = Arrays.stream(team).filter(x -> x.getType() == Type.KING).findFirst()
                .orElse(null);
        return (King) theKing;
    }

我的问题被修复了，但我还是不知道。为什么那修复了我的代码？为什么它之前不工作？
Piece是一个抽象类，team是玩家棋子的数组。