Method for extracting the added alias

http-netty/src/main/java/io/micronaut/http/netty/NettyTlsUtils.java

@@ -24,6 +24,7 @@
 import io.netty.handler.ssl.SslProvider;
 
 import javax.net.ssl.KeyManagerFactory;
+import java.security.Key;
 import java.security.KeyStore;
 import java.util.Optional;
 
@@ -79,7 +80,25 @@ public static KeyManagerFactory storeToFactory(@NonNull SslConfiguration ssl, @N
         if (keyPassword == null && pwd.isPresent()) {
             keyPassword = pwd.get().toCharArray();
         }
+        if (keyStore != null && ssl.getKey().getAlias().isPresent()) {
+            keyStore = extractKeystoreAlias(keyStore, ssl.getKey().getAlias().get(), keyPassword);
+        }
         keyManagerFactory.init(keyStore, keyPassword);
         return keyManagerFactory;
     }
+
+    private static KeyStore extractKeystoreAlias(@NonNull KeyStore rootKeystore, @NonNull String alias, @Nullable char[] password) throws Exception {
+        if (!rootKeystore.containsAlias(alias)) {
+            throw new IllegalArgumentException("Alias " + alias + " not found in keystore.");
+        }
+        Key key = rootKeystore.getKey(alias, password);
+        if (key == null) {
+            throw new IllegalStateException("There are no keys associated with the alias " + alias);
+        }
+        java.security.cert.Certificate[] certChain = rootKeystore.getCertificateChain(alias);
+        KeyStore aliasKeystore = KeyStore.getInstance(rootKeystore.getType());
+        aliasKeystore.load(null, null);
+        aliasKeystore.setKeyEntry(alias, key, password, certChain);
+        return aliasKeystore;
+    }
 }