Java Objects Exercise

./ScrabblePlayer.java:21: error: incompatible types: String cannot be converted to char
      tile += tiles;

public class ScrabblePlayer {
  // A String representing all of the tiles that this player has
  private String tiles;

  public ScrabblePlayer() {
    tiles = "";
  }

  public String getTiles() {
    return tiles;
  }

  public void addTile(char tile) {
    // TODO: Add the tile to tiles
  }

  public boolean hasTile(char tile) {
    // TODO: Determine if user has the tile passed in
    boolean giveTile = tiles.indexOf(tile) != -1;
    if (giveTile) {
      tile += tiles;
    }
    return false;
  }

}