I apologize, but there is no such class as "UTF8Writer" in the Apache Commons IO library. It seems that you might be confusing it with other class or package. Apache Commons IO focuses on providing utility classes for file and I/O operations, and it doesn't have a class specifically for writing UTF-8 encoded text.

Java provides the OutputStreamWriter class which can be used to write text to an OutputStream. The OutputStreamWriter class can be used to specify the character encoding of the output stream. To write UTF-8 encoded text, you can use the OutputStreamWriter class with the "UTF-8" character encoding.

Here is an example of using the OutputStreamWriter class to write UTF-8 encoded text to a file:

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;

public class UTF8WriterExample {
    public static void main(String[] args) throws IOException {
        FileOutputStream fos = new FileOutputStream("file.txt");
        OutputStreamWriter writer = new OutputStreamWriter(fos, "UTF-8");
        String text = "This is a test string.";
        writer.write(text);
        writer.flush();
        writer.close();
    }
}