some docu resulting from issue#2

Author: gschwab

README.md

@@ -348,3 +348,15 @@ Now an edge can be created to set a relation between vertices
       null,
       null);
 ``` 
+
+# Known bugs
+Due to deserializition of some attribute combinations of name/type may lead to exceptions.
+These combinations are:
+
+| attribute name | attribute type |
+|----------------|----------------|
+| error          | boolean        |
+| code           | numeric        |
+| errorNum       | numeric        |
+| errorMessage   | String         |
+| etag           | numeric        |

src/main/java/com/arangodb/entity/EntityDeserializers.java

@@ -136,7 +136,7 @@ private static Class<?> backParameterized() {
   }
 
   private static <T extends BaseEntity> T deserializeBaseParameter(JsonObject obj, T entity) {
-    if (obj.has("error")) {
+    if (obj.has("error") && obj.getAsJsonPrimitive("error").isBoolean()) {
       entity.error = obj.getAsJsonPrimitive("error").getAsBoolean();
     }
     if (obj.has("code") && obj.getAsJsonPrimitive("code").isNumber()) {