import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

/*
 * public FileWriter(File file, boolean append) 
 *                             throws IOException
 * 
 * Parameters: 
 * ----------
 * 
 * file - a File object to write to
 * 
 * append - if true, then bytes will be written to the
 * end of the file rather than the beginning
 */
public class FileWriterDemo
{
    public static void main(String[] args) throws IOException
    {
        FileWriterDemo fileWriterDemo = new FileWriterDemo();
        fileWriterDemo.writeFile();
    }

    private void writeFile() throws IOException
    {
        FileWriter fileWriter = null;

        try
        {

            File file = new File("myfile.txt");

            /*
             * Constructs a FileWriter object given a File
             * object. If the second argument is true, then
             * bytes will be written to the end of the file
             * rather than the beginning.
             */
            fileWriter = new FileWriter(file, true);
            /*
             * Writes a string.
             */
            fileWriter.write("Welcome to America.\n");
            System.out.println("Successfully written to the file."
                    + "please check the file content.");
        }
        finally
        {
            if (fileWriter != null)
            {
                /*
                 * Closes the stream, flushing it first.
                 * Once the stream has been closed, further
                 * write() or flush() invocations will cause
                 * an IOException to be thrown. Closing a
                 * previously closed stream has no effect.
                 */
                fileWriter.close();
            }
        }
    }

}

Successfully written to the file.please check the file content.