Java Programming

package testfilewriter;

import java.io.*;


public class Main {
    
    static FileWriter obj;

    public static void main(String[] args) {
        try
        {
            obj = new FileWriter("/a.txt",true);
            obj.write("hi!");
            obj.flush();
            obj.close();
        }
        catch(Exception e)
        {
            System.out.println("exception");
        }
       
    }

}

netbeans on mac with default language US english. the program writes a chinese character to the file instead of hi!