Start implementing #540

src/main/java/com/fasterxml/jackson/databind/DeserializationFeature.java

@@ -243,12 +243,27 @@ public enum DeserializationFeature implements ConfigFeature
      * If disabled, standard POJOs can only be bound from JSON null or
      * JSON Object (standard meaning that no custom deserializers or
      * constructors are defined; both of which can add support for other
-     * kinds of JSON values); if enable, empty JSON String can be taken
+     * kinds of JSON values); if enabled, empty JSON String can be taken
      * to be equivalent of JSON null.
      *<p>
      * Feature is disabled by default.
      */
     ACCEPT_EMPTY_STRING_AS_NULL_OBJECT(false),
+
+    /**
+     * Feature that can be enabled to allow empty JSON Array
+     * value (that is, <code>[ ]</code>) to be bound to POJOs as null.
+     * If disabled, standard POJOs can only be bound from JSON null or
+     * JSON Object (standard meaning that no custom deserializers or
+     * constructors are defined; both of which can add support for other
+     * kinds of JSON values); if enabled, empty JSON Array will be taken
+     * to be equivalent of JSON null.
+     *<p>
+     * Feature is disabled by default.
+     * 
+     * @since 2.5
+     */
+    ACCEPT_EMPTY_ARRAY_AS_NULL_OBJECT(false),
 
     /**
      * Feature that allows unknown Enum values to be parsed as null values. 

src/main/java/com/fasterxml/jackson/databind/deser/BeanDeserializerBase.java

@@ -30,7 +30,7 @@ public abstract class BeanDeserializerBase
     implements ContextualDeserializer, ResolvableDeserializer,
         java.io.Serializable // since 2.1
 {
-    private static final long serialVersionUID = 2960120955735322578L;
+    private static final long serialVersionUID = 1;
 
     protected final static PropertyName TEMP_PROPERTY_NAME = new PropertyName("#temporary-name");
 

src/test/java/com/fasterxml/jackson/databind/creators/TestBuilderSimple.java

@@ -26,13 +26,13 @@ static class SimpleBuilderXY
     {
         public int x, y;
 
-        public SimpleBuilderXY withX(int x) {
-    		    this.x = x;
+        public SimpleBuilderXY withX(int x0) {
+    		    this.x = x0;
     		    return this;
         }
 
-        public SimpleBuilderXY withY(int y) {
-    		    this.y = y;
+        public SimpleBuilderXY withY(int y0) {
+    		    this.y = y0;
     		    return this;
         }
 
@@ -61,15 +61,15 @@ static class BuildABC
         private int b, c;
 
         @JsonProperty("b")
-        public BuildABC assignB(int b) {
-            this.b = b;
+        public BuildABC assignB(int b0) {
+            this.b = b0;
             return this;
         }
 
         // Also ok NOT to return 'this'
         @JsonSetter("c")
-        public void c(int c) {
-            this.c = c;
+        public void c(int c0) {
+            this.c = c0;
         }
 
         public ValueClassABC build() {

src/test/java/com/fasterxml/jackson/databind/deser/TestBeanDeserializer.java

@@ -223,6 +223,8 @@ public Object deserializeKey(String key,
     /********************************************************
      */
 
+    private final ObjectMapper MAPPER = new ObjectMapper();
+
     public void testPropertyRemoval() throws Exception
     {
         ObjectMapper mapper = new ObjectMapper();
@@ -258,22 +260,43 @@ public void testIssue476() throws Exception
     public void testPOJOFromEmptyString() throws Exception
     {
         // first, verify default settings which do not accept empty String:
-        ObjectMapper mapper = new ObjectMapper();
+        assertFalse(MAPPER.isEnabled(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT));
         try {
-            mapper.readValue(quote(""), Bean.class);
+            MAPPER.readValue(quote(""), Bean.class);
             fail("Should not accept Empty String for POJO");
         } catch (JsonProcessingException e) {
             verifyException(e, "from String value");
             assertValidLocation(e.getLocation());
         }
+        // should be ok to enable dynamically
+        ObjectReader r = MAPPER.reader(Bean.class)
+                .with(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT);
+        Bean result = r.readValue(quote(""));
+        assertNull(result);
+    }
+
+    // [Databind#540]
+    public void testPOJOFromEmptyArray() throws Exception
+    {
+        final String JSON = "  [\n]";
+        assertFalse(MAPPER.isEnabled(DeserializationFeature.ACCEPT_EMPTY_ARRAY_AS_NULL_OBJECT));
+        // first, verify default settings which do not accept empty Array
+        ObjectMapper mapper = new ObjectMapper();
+        try {
+            mapper.readValue(JSON, Bean.class);
+            fail("Should not accept Empty Array for POJO by default");
+        } catch (JsonProcessingException e) {
+            verifyException(e, "START_ARRAY token");
+            assertValidLocation(e.getLocation());
+        }
 
         // should be ok to enable dynamically:
-        mapper = new ObjectMapper();
-        mapper.configure(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT, true);
-        Bean result = mapper.readValue(quote(""), Bean.class);
+        ObjectReader r = MAPPER.reader(Bean.class)
+                .with(DeserializationFeature.ACCEPT_EMPTY_ARRAY_AS_NULL_OBJECT);
+        Bean result = r.readValue(JSON);
         assertNull(result);
     }
-
+    
     // [Issue#120]
     public void testModifyArrayDeserializer() throws Exception
     {

src/test/java/com/fasterxml/jackson/databind/introspect/TestBuilderMethods.java

@@ -13,8 +13,8 @@ static class SimpleBuilder
     {
         public int x;
 
-        public SimpleBuilder withX(int x) {
-    		    this.x = x;
+        public SimpleBuilder withX(int x0) {
+    		    this.x = x0;
     		    return this;
         }
     }