fix test

Author: taowen

src/main/java/com/jsoniter/spi/Config.java

@@ -418,9 +418,11 @@ private void updateBindings(ClassDescriptor desc) {
                 desc.onExtraProperties = binding;
             }
             if (annotated && binding.field != null) {
-                for (Binding setter : desc.setters) {
-                    if (binding.name.equals(setter.name)) {
-                        throw new JsonException("annotation should be marked on getter/setter for field: " + binding.name);
+                if (desc.setters != null) {
+                    for (Binding setter : desc.setters) {
+                        if (binding.name.equals(setter.name)) {
+                            throw new JsonException("annotation should be marked on getter/setter for field: " + binding.name);
+                        }
                     }
                 }
             }

src/test/java/com/jsoniter/TestAnnotationJsonProperty.java

@@ -5,6 +5,7 @@
 import com.jsoniter.annotation.JsonProperty;
 import com.jsoniter.fuzzy.StringIntDecoder;
 import com.jsoniter.output.JsonStream;
+import com.jsoniter.spi.DecodingMode;
 import com.jsoniter.spi.JsonException;
 import junit.framework.TestCase;
 
@@ -145,12 +146,16 @@ public void test_getter_and_setter() throws IOException {
     }
 
     public static class TestObject10 {
-        public int field;
+        private int field;
 
         @JsonCreator
         public TestObject10(@JsonProperty("hello") int field) {
             this.field = field;
         }
+
+        public int getField() {
+            return field;
+        }
     }
 
     public void test_creator_with_json_property() {