import java.io.FileInputStream;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
public class MainClass {
public static void main(String[] args) throws Exception {
CertificateFactory certFactory = CertificateFactory.getInstance("X.509");
FileInputStream fis = new FileInputStream("a.dat");
Certificate cert = certFactory.generateCertificate(fis);
fis.close();
System.out.println(cert);
}
}