import java.io.File;
import java.io.RandomAccessFile;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;
public class Main {
public static void main(String[] argv) throws Exception {
File file = new File("filename");
FileChannel channel = new RandomAccessFile(file, "rw").getChannel();
FileLock lock = channel.lock(0, Long.MAX_VALUE, true);
lock = channel.tryLock(0, Long.MAX_VALUE, true);
boolean isShared = lock.isShared();
lock.release();
channel.close();
}
}