Wie kann ein Java-Client mit selbstsignierten SSL-Zertifikaten umgehen?

sun.security.validator.ValidatorException: PKIX path building failed

<JAVA_HOME>/bin/keytool -import -v -trustcacerts \
-alias server-alias -file server.cer \
-keystore cacerts.jks -keypass changeit \
-storepass changeit

// Trust manager that does not validate certificate chains
TrustManager[] trustAllCerts = new TrustManager[] {
    new X509TrustManager() {
        @Override
        public void checkClientTrusted(X509Certificate[] certs, String authType) {}
        @Override
        public void checkServerTrusted(X509Certificate[] certs, String authType) {}
        @Override
        public X509Certificate[] getAcceptedIssuers() { return new X509Certificate[0]; }
    }
};

// Install trust manager
SSLContext sc = SSLContext.getInstance("SSL");
sc.init(null, trustAllCerts, new SecureRandom());
HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());