igonre "isSynthetic" method when eagerly validating (#3864)

* igonre "isSynthetic" method when eagerly validating

* Update retrofit/src/main/java/retrofit2/Retrofit.java

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Co-authored-by: yanpengyanpeng <[email protected]>
Co-authored-by: Jake Wharton <[email protected]>

Author: 3 people

retrofit/src/main/java/retrofit2/Retrofit.java

@@ -191,7 +191,9 @@ private void validateServiceInterface(Class<?> service) {
     if (validateEagerly) {
       Platform platform = Platform.get();
       for (Method method : service.getDeclaredMethods()) {
-        if (!platform.isDefaultMethod(method) && !Modifier.isStatic(method.getModifiers())) {
+        if (!platform.isDefaultMethod(method)
+            && !Modifier.isStatic(method.getModifiers())
+            && !method.isSynthetic()) {
           loadServiceMethod(service, method);
         }
       }