Arguments in Java?

Arguments are variables that are utilized by that object in a class only. The method uses the argument to declare things

public void addTile(char tile); mHand+=tile;

public boolean hasTile(char tile); boolean hasTile=mHand.indexOf(tile)!=1; return false;

The char tile (char tile) is the same name in two different methods. Is this the same variable throughout the class or is it unique to the method? I know that the name of each (addTile and hasTile) are different and it necessarily wouldn't matter, I wouldn't think. The only reason I would think it was the same is because of char tile.

I'm trying to understand the logic and this has just slightly tripped me up. Thanks!

public class ScrabblePlayer {
    private String mHand;

    public ScrabblePlayer() {
        mHand = "";
    }

    public String getHand() {
       return mHand;
    }

    public void addTile(char tile) {
     mHand += tile;

    }

    public boolean hasTile(char tile) {
     boolean hasTile = mHand.indexOf(tile) != -1;
       return false;
    }
}