code: public void setIdentityFromPrivateKey( String privateKey, String passPhrase ) throws JSchException {
          clearIdentityRepository();
          jsch.addIdentity( privateKey, passPhrase );
      }
docs: Configures this factory to use a single identity authenticated by the
  supplied private key and pass phrase. The private key should be the path
  to a private key file in OpenSSH format. Clears out the current
  {@link IdentityRepository} before adding this key.
  
  @param privateKey
  Path to a private key file
  @param passPhrase
  Pass phrase for private key
  @throws JSchException
  If the key is invalid