Here is an example of how to use the ThresholdingOutputStream class from the org.apache.commons.io package in Java:

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

import org.apache.commons.io.output.ThresholdingOutputStream;

public class Example {
    public static void main(String[] args) throws IOException {
        FileOutputStream fileOutputStream = new FileOutputStream("example.txt");
        ThresholdingOutputStream thresholdingOutputStream = new ThresholdingOutputStream(100, fileOutputStream);
        thresholdingOutputStream.write("Hello, World!".getBytes());
        thresholdingOutputStream.flush();
        thresholdingOutputStream.close();
    }
}

This example creates a FileOutputStream to write to a file named "example.txt", and then wraps it in a ThresholdingOutputStream. The ThresholdingOutputStream class has a threshold of 100 bytes. The write method is called on the thresholdingOutputStream object to write the bytes of the string "Hello, World!" to the file. The flush method is called to flush any remaining bytes to the file, and the close method is called to close the stream.

You can also use your own implementation of the OutputStream by extending the ThresholdingOutputStream class and passing it to the super class constructor, you can use the write method and other methods to execute your own logic, for example, you can use it to limit the size of the file, or for any other purpose.

Note that, the ThresholdingOutputStream is not intended to be used as a general-purpose class, it is intended to be used only in situations where you need to write a stream to a file and also set a threshold limit on the size of the file.