Improve the robustness of getResourceAsStream() in Utils.java.

core/src/main/java/com/predic8/membrane/core/openapi/util/Utils.java

@@ -26,10 +26,16 @@
 import jakarta.mail.internet.*;
 
 import java.io.*;
+import java.net.URL;
 import java.time.*;
 import java.time.format.*;
 import java.util.*;
 import java.util.regex.*;
+import java.io.FileInputStream;
+import java.io.InputStream;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URL;
 
 import static com.predic8.membrane.core.exchange.Exchange.*;
 import static java.nio.charset.StandardCharsets.*;
@@ -200,9 +206,23 @@ public static String normalizeForId(String s) {
     }
 
     public static InputStream getResourceAsStream(Object obj, String fileName) {
-        return obj.getClass().getResourceAsStream(fileName);
+        try {
+            URL url = obj.getClass().getResource(fileName);
+            if (url == null) {
+                return null;
+            }
+
+            return new FileInputStream(new URI(url.toString()).getPath());
+        } catch (URISyntaxException | IOException e) {
+            e.printStackTrace();
+            return null;
+        }
     }
 
+    /*public static InputStream getResourceAsStream(Object obj, String fileName) {
+        return obj.getClass().getResourceAsStream(fileName);
+    }*/
+
     public static byte[] createErrorMessage(String msg) {
         return String.format("{ \"error\": \"%s\" }",msg).getBytes();
     }