To add a file in GZIP format you need to use java.util.zip.GZIPOutputStream class. An example of writing a text file in GZIP format is given below,

Java Write GZIP File Example
To add a file in GZIP format you need to use java.util.zip.GZIPOutputStream class. An example of writing a text file in GZIP format is given below,
JavaWriteToGZIPFileExample.java
import java.io.FileOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.zip.GZIPOutputStream;
public class JavaWriteToGZIPFileExample{
public static void main(String[] args) throws IOException{
/* The new file name which you will get */
String newFileName = "myNewCompressedFile.gzip";
FileOutputStream fileOutputStream = new FileOutputStream(newFileName);
/* GZIPOutputStream class to compress the file */
GZIPOutputStream outputStream = new GZIPOutputStream(fileOutputStream);
/* The file which you have to compress */
String fileToCompress = "myTextFile.txt";
FileInputStream inputStream = new FileInputStream(fileToCompress);
/* Creating a Buffer to Transfer a file */
byte []buffer = new byte[1024];
int length;
while ((length = inputStream.read(buffer)) > 0) {
outputStream.write(buffer, 0, length);
}
/* Finally closing the GZIPOutputStream and FileInputStream classes */
inputStream.close();
outputStream.close();
}
}