public class Token
{
    public static final char SPACE = ' ';
    public static final char PLUS = '+';
    public static final char MULTIPLY = '*';
    public static final char OPEN_BRACE = '(';
    public static final char CLOSE_BRACE = ')';
    
    private Token ()
    {
    }
}
public class Tokens
{
    public static final char SPACE = ' ';
    public static final char PLUS = '+';
    public static final char MULTIPLY = '*';
    public static final char OPEN_BRACE = '(';
    public static final char CLOSE_BRACE = ')';

    private Tokens ()
    {
    }
}
Update Tokens.java