Getting a Certificate from a Keystore

 try {
   KeyStore keyStore = KeyStore.getInstance(
     KeyStore.getDefaultType());
     
   InputStream in = new FileInputStream(".keystore");
   keyStore.load(in, "password".toCharArray());
     
   java.security.cert.Certificate cert = 
     keyStore.getCertificate("Principal");
   process(cert);
 }  catch (KeyStoreException e) {
 } catch (java.security.cert.CertificateException e) {
 } catch (NoSuchAlgorithmException e) {
 } catch (java.io.IOException e) {
 }