GZIPOutputStream is a Java class that provides functionality for compressing data using the GZIP compression format. It is used in conjunction with OutputStream to write compressed data to a file or other output destination.

Here is an example of how to use GZIPOutputStream to compress data and write it to a file:

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.GZIPOutputStream;

public class GZipExample {
    public static void main(String[] args) {
        try (FileOutputStream fileOutputStream = new FileOutputStream("compressedFile.gz");
             GZIPOutputStream gzipOutputStream = new GZIPOutputStream(fileOutputStream)) {
            // write data to the GZIPOutputStream here
            gzipOutputStream.write("This is some data to compress.".getBytes());
            gzipOutputStream.finish(); // finalize the compressed data
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

In this example, we first create a FileOutputStream object to write data to the output file. We then pass this object to the constructor of GZIPOutputStream, which creates a new GZIPOutputStream object that compresses and writes data to the output file. We then write the data to the GZIPOutputStream using the write method, and finalize the compressed data using the finish method.

Note that we are using the try-with-resources statement to ensure that the FileOutputStream and GZIPOutputStream objects are closed properly when we are done writing data to the file.