Fix for NullPointer when using Json support without configured charset.

Signed-off-by: Tomas Langer <[email protected]>

media/jsonp/server/src/main/java/io/helidon/media/jsonp/server/JsonSupport.java

@@ -18,6 +18,7 @@
 
 import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.util.List;
 import java.util.Objects;
 import java.util.function.Function;
@@ -185,7 +186,7 @@ private boolean testOrSetContentType(ServerRequest request, ServerResponse respo
      * Returns a charset from {@code Content-Type} header parameter or {@code null} if not defined.
      *
      * @param headers parameters representing request or response headers
-     * @return a charset or {@code null}
+     * @return a charset or {@code UTF-8} as default
      * @throws RuntimeException if charset is not supported
      */
     private Charset determineCharset(Parameters headers) {
@@ -199,7 +200,7 @@ private Charset determineCharset(Parameters headers) {
                         return null; // Do not need default charset. Can use JSON specification.
                     }
                 })
-                .orElse(null);
+                .orElse(StandardCharsets.UTF_8);
     }
 
     /**