import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.PosixFilePermission;
import java.util.Set;

public class TestFilePermissions {

	public static void main(String[] args) {
		try { 
		     Path path = Paths.get("/tmp", "foo"); 

		     Set<PosixFilePermission> perms = Files.getPosixFilePermissions(path); 
		     perms.add(PosixFilePermission.GROUP_WRITE); 

		     Files.setPosixFilePermissions(path, perms); 
		 } 
		 catch (IOException e) { 
		     e.printStackTrace(); 
		 } 

	}

}