Modifying a field in a data object is resulting in Unrecognized field exception

Question

I have the following very simple POJO object

Working Version

package com.example.model;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement 
public class Employee {
    long id;
    String firstName;
    String lastName;

    public long getId() {
        return id;
    }
    public void setId(long l) {
        this.id = l;
    }
    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
}

JSON request body that i used

{"id":"23", "firstName":"John", "lastName":"Smith"}

Modified Version which is resulting in Unrecognized Field

package com.example.model;


public class Employee {
    long id;
    **String firstEmpName;**  // Resulting in unrecognized Field
    **String lastEmpName;**   // Resulting in Unrecognized Field

    public long getId() {
        return id;
    }
    public void setId(long l) {
        this.id = l;
    }
    public String getFirstName() {
        return firstEmpName;
    }
    public void setFirstName(String firstName) {
        this.firstEmpName = firstName;
    }
    public String getLastName() {
        return lastEmpName;
    }
    public void setLastName(String lastName) {
        this.lastEmpName = lastName;
    }
}

After changing the first name and last name to firstEmpName and lastEmpName, i tried to post the below request body

JSON request body that i used

{"id":"23", "firstEmpName":"John", "lastEmpName":"Smith"}

Exception i got

org.codehaus.jackson.map.exc.UnrecognizedPropertyException: Unrecognized field "firstEmpName" (Class com.example.model.Employee), not marked as ignorable
 at [Source: org.restlet.engine.io.UnclosableInputStream@2275a30f; line: 1, column: 29] (through reference chain: com.example.model.Employee["firstEmpName"])
    at org.codehaus.jackson.map.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:53)
    at org.codehaus.jackson.map.deser.StdDeserializationContext.unknownFieldException(StdDeserializationContext.java:267)
    at org.codehaus.jackson.map.deser.std.StdDeserializer.reportUnknownProperty(StdDeserializer.java:673)

Rest of the sample application is as follows:

@Override
public Restlet createInboundRoot() {

// Create a router Restlet that routes each call to a
    // new instance of HelloWorldResource.
    Router router = new Router(getContext());

    // Defines only one route
    router.attach("/employees/{id}", SampleAppRestlet_ServerServlet.class);


    return router;
}




      public class SampleAppRestlet_ServerServlet extends ServerResource {
         @Get
        public Employee getEmployee(){

                Employee m = new Employee();
                m.setFirstName("John");
                m.setLastName("Smith");
                m.setId(23);

                return m;

        }
    }

Everytime i change a field name, do i need to do something for that field to be recognized.

I also tried using Jax-rs instead of Restlet, i still see the same problem.

So to summarize the problem that i am having, whatever the pojo that i create in the first time is what remains and is working. If i changing any fields in the POJO like that of above, for example from firstName to firstEmpName, then i get the above exception. I tried to clean the classes, restarted the server. Removed local_db.bin and even changed the Pojo class name to a different and tried but still it is not working. BTW, i am using Google App engine. The restlet sdk i used was the GAE edition of Restlet sdk. Also i tried with JAX-RS. I resolved the library conflicts and everything works the first time i try and if i change the field names, then in the case JAX-RS, it silently ignores those fields whose names have been changed.

Any guess or thoughts or suggestions is much appreciated.

Answer 1

Properties in Java Beans are defined by the method names, not the field names. So you should rename the get and set methods to match the field names.