GZIPInputStream is a Java class that provides functionality for reading data that has been compressed using the GZIP compression format. It is used in conjunction with InputStream to read data from a compressed file.

Here is an example of how to use GZIPInputStream to read data from a compressed file:

import java.io.FileInputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;

public class GZipExample {
    public static void main(String[] args) {
        try (FileInputStream fileInputStream = new FileInputStream("compressedFile.gz");
             GZIPInputStream gzipInputStream = new GZIPInputStream(fileInputStream)) {
            byte[] buffer = new byte[1024];
            int length;
            while ((length = gzipInputStream.read(buffer)) != -1) {
                // process the data here
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

In this example, we first create a FileInputStream object to read data from the compressed file. We then pass this object to the constructor of GZIPInputStream, which creates a new GZIPInputStream object that reads data from the compressed file. We then read the compressed data from the GZIPInputStream using a buffer and process the data as needed.

Note that we are using the try-with-resources statement to ensure that the FileInputStream and GZIPInputStream objects are closed properly when we are done reading data from the file.