question: public static RSAPrivateKey loadFromKeyStore ( URL keystoreUrl , String password ) throws IOException , NoSuchAlgorithmException , CertificateException , KeyStoreException , UnrecoverableKeyException { logger . debug ( "loadFromKeyStore: keystoreUrl={}" , keystoreUrl ) ; URLConnection connection = keystoreUrl . openConnection ( ) ; InputStream is = connection . getInputStream ( ) ; try { if ( logger . isDebugEnabled ( ) ) logger . debug ( "getproviders={}" , Arrays . toString ( Security . getProviders ( ) ) ) ; KeyStore keyStore ; try { try { keyStore = KeyStore . getInstance ( "PKCS12" , "SunJSSE" ) ; } catch ( NoSuchProviderException e ) { keyStore = KeyStore . getInstance ( "PKCS12" , CryptoUtil . getSecurityProviderName ( KeyStore . class ) ) ; } } catch ( NoSuchProviderException e ) { keyStore = KeyStore . getInstance ( "PKCS12" ) ; } logger . debug ( "loadFromKeyStore: keyStore Provider={}" , keyStore . getProvider ( ) ) ; keyStore . load ( is , password == null ? null : password . toCharArray ( ) ) ; Enumeration < String > aliases = keyStore . aliases ( ) ; Key key = null ; while ( aliases . hasMoreElements ( ) ) { String a = ( String ) aliases . nextElement ( ) ; key = keyStore . getKey ( a , password == null ? null : password . toCharArray ( ) ) ; } return ( RSAPrivateKey ) key ; } finally { is . close ( ) ; } }
target:  Load private key from a key store