DATACMNS-1828 - Fix Map component type lookup for custom Map implementations.

Instead of using the first generic type parameter of a parameterized type as Map component type, we now explicitly lookup the super type's Map-specific generics configuration and use its first generic type parameter. The same for collection like types falling back to the parameter type bound to Iterable.

src/main/java/org/springframework/data/util/ParameterizedTypeInformation.java

@@ -156,6 +156,17 @@ class ParameterizedTypeInformation<T> extends ParentTypeAwareTypeInformation<T>
 	@Override
 	@Nullable
 	protected TypeInformation<?> doGetComponentType() {
+
+		boolean isCustomMapImplementation = isMap() && !getType().equals(Map.class);
+
+		if (isCustomMapImplementation) {
+			return getRequiredSuperTypeInformation(Map.class).getComponentType();
+		}
+
+		if (isCollectionLike() && !getType().getPackage().getName().startsWith("java.")) {
+			return getRequiredSuperTypeInformation(Iterable.class).getComponentType();
+		}
+
 		return createInfo(type.getActualTypeArguments()[0]);
 	}