bug fix for MethodInheritanceComparator

Author: wenshao

src/main/java/com/alibaba/fastjson/util/TypeUtils.java

@@ -1916,6 +1916,12 @@ public static List<FieldInfo> computeGetters(Class<?> clazz, //
         String[] paramNames = null;
         short[] paramNameMapping = null;
         Method[] methods = clazz.getMethods();
+        try {
+            Arrays.sort(methods, new MethodInheritanceComparator());
+        } catch (Throwable ignored) {
+
+        }
+
         for (Method method : methods) {
             String methodName = method.getName();
             int ordinal = 0, serialzeFeatures = 0, parserFeatures = 0;
@@ -3424,4 +3430,29 @@ public static Object optionalEmpty(Type type) {
         }
         return null;
     }
+
+    public static class MethodInheritanceComparator implements Comparator<Method> {
+        public int compare(Method m1, Method m2) {
+            int cmp = m1.getName().compareTo(m2.getName());
+            if (cmp != 0) {
+                return cmp;
+            }
+
+            Class<?> class1 = m1.getReturnType();
+            Class<?> class2 = m2.getReturnType();
+
+            if (class1.equals(class2)) {
+                return 0;
+            }
+
+            if (class1.isAssignableFrom(class2)) {
+                return -1;
+            }
+            
+            if (class2.isAssignableFrom(class1)) {
+                return 1;
+            }
+            return 0;
+        }
+    }
 }