No String-argument constructor/factory method to deserialize from String value ('')

Question

I'm running into a json parsing issue when using the ObjectMapper class from the com.fasterxml.jackson.databind package, and the error that I'm getting is:

com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of com.graybar.utilities.ups.beans.Address: no String-argument constructor/factory method to deserialize from String value ('') 

The web application where this problem is occurring is a Spring MVC application using an AngularJS front end, but I can duplicate the issue with a much smaller, all java program. Here are my beans:

Shipment.java

@JsonIgnoreProperties(ignoreUnknown = true) public class Shipment {     @JsonProperty("Activity")     private ArrayList<Activity> activity;     public ArrayList<Activity> getActivity() {         return activity;     }     public void setActivity(ArrayList<Activity> activity) {         this.activity = activity;     } } 

Activity.java

@JsonIgnoreProperties(ignoreUnknown = true) public class Activity {     @JsonProperty("ActivityLocation")     private ArrayList<ActivityLocation> activityLocation;     public ArrayList<ActivityLocation> getActivityLocation() {         return activityLocation;     }     public void setActivityLocation(ArrayList<ActivityLocation> activityLocation) {         this.activityLocation = activityLocation;     } } 

ActivityLocation.java

@JsonIgnoreProperties(ignoreUnknown = true) public class ActivityLocation {     @JsonProperty("Address")     private Address address;     public Address getAddress() {         return address;     }     public void setAddress(Address address) {         this.address = address;     } } 

Address.java

@JsonIgnoreProperties(ignoreUnknown = true) public class Address {     @JsonProperty("City")     private String city;     @JsonProperty("StateProvinceCode")     private String stateProvinceCode;     @JsonProperty("CountryCode")     private String countryCode;     public String getCity() {         return city;     }     public void setCity(String city) {         this.city = city;     }     public String getCountryCode() {         return countryCode;     }     public void setCountryCode(String countryCode) {         this.countryCode = countryCode;     }     public String getStateProvinceCode() {         return stateProvinceCode;     }     public void setStateProvinceCode(String stateProvinceCode) {         this.stateProvinceCode = stateProvinceCode;     } } 

Here is the code where I can properly map the json:

public static void main(String[] args) {     String jsonMessage = "" +         "{" +          "   \"Activity\": [{ " +         "       \"ActivityLocation\": { " +         "           \"Address\": { " +         "               \"City\": \"Hana\", " +         "               \"StateProvinceCode\": \"Hi\", " +         "               \"CountryCode\": \"US\" " +         "           } " +         "       } " +         "   }, " +         "   { " +         "       \"ActivityLocation\": { " +         "           \"Address\": { " +         "               \"City\": \"Honolulu\", " +         "               \"StateProvinceCode\": \"Hi\", " +         "               \"CountryCode\": \"US\" " +         "           } " +         "       } " +         "   }] " +     "} ";      try {         ObjectMapper mapper = new ObjectMapper();         mapper.enable(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY);          Shipment shipment = mapper.readValue(jsonMessage, Shipment.class);         System.out.println("shipment.toString = " + shipment.toString());     } catch (Exception e) {         e.printStackTrace();     } } 

When adjusting the data in the jsonMessage var is when I run into the error that I mentioned above:

    "{" +      "   \"Activity\": [{ " +     "       \"ActivityLocation\": { " +     "           \"Address\": { " +     "               \"City\": \"Hana\", " +     "               \"StateProvinceCode\": \"Hi\", " +     "               \"CountryCode\": \"US\" " +     "           } " +     "       } " +     "   }, " +     "   { " +     "       \"ActivityLocation\": { " +     "           \"Address\": \"\" " +     "           } " +     "       } " +     "   }] " +     "} "; 

So, the problem happens when changing the json from this:

{     "ActivityLocation": {          "Address": {             "City": "Honolulu",              "StateProvinceCode": "Hi",              "CountryCode": "US"         }     } }] 

to this:

{ "ActivityLocation": {      "Address": ""     } } 

Instead of sending values for my Address bean, I'm getting just an empty string. Unfortunately, I'm receiving my data from a third party and have no control over the data I receive.

Is there an annotation that needs to be added to be able to handle this?

Answer 1

Had this when I accidentally was calling

mapper.convertValue(...) 

instead of

mapper.readValue(...) 

So, just make sure you call correct method, since argument are same and IDE can find many things