From 2db1fe2c9311be4371bcc654b84e4951f7d4ee08 Mon Sep 17 00:00:00 2001
From: tarekmamdouh <tarek_mamdouh@hotmail.com>
Date: Wed, 27 Oct 2021 05:54:52 -0400
Subject: [PATCH] Add support for generic types in synthetic classes such as
 weld proxies (#2589) (#2754)

Co-authored-by: Tarek Ahmed <tarek.ahmed@agfa.com>
---
 .../java/ca/uhn/fhir/rest/server/method/MethodUtil.java  | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/method/MethodUtil.java b/hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/method/MethodUtil.java
index 31a608c2846..6c05f216ae4 100644
--- a/hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/method/MethodUtil.java
+++ b/hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/method/MethodUtil.java
@@ -90,6 +90,15 @@ public class MethodUtil {
 				if (Collection.class.isAssignableFrom(parameterType)) {
 					innerCollectionType = (Class<? extends java.util.Collection<?>>) parameterType;
 					parameterType = ReflectionUtil.getGenericCollectionTypeOfMethodParameter(theMethod, paramIndex);
+					if(parameterType == null && theMethod.getDeclaringClass().isSynthetic()) {
+						try {
+							theMethod = theMethod.getDeclaringClass().getSuperclass().getMethod(theMethod.getName(), parameterTypes);
+							parameterType = ReflectionUtil.getGenericCollectionTypeOfMethodParameter(theMethod, paramIndex);
+						} catch (NoSuchMethodException e) {
+							throw new ConfigurationException("A method with name '" + theMethod.getName() + "' does not exist for super class '"
+								+ theMethod.getDeclaringClass().getSuperclass() + "'");
+						}
+					}
 					declaredParameterType = parameterType;
 				}
 				if (Collection.class.isAssignableFrom(parameterType)) {