Getting HTTP Status 415 - Unsupported Media Type from Jersey

Below is my POJO class

public class Credentials {
private int cred_id;
private String cred_user_name;
private String cred_password;
private String cred_token;

public Credentials(int cred_id, String cred_user_name,
        String cred_password, String cred_token) {
    this.cred_id = cred_id;
    this.cred_user_name = cred_user_name;
    this.cred_password = cred_password;
    this.cred_token = cred_token;
}

public int getCred_id() {
    return cred_id;
}

public void setCred_id(int cred_id) {
    this.cred_id = cred_id;
}

public String getCred_user_name() {
    return cred_user_name;
}

public void setCred_user_name(String cred_user_name) {
    this.cred_user_name = cred_user_name;
}

public String getCred_password() {
    return cred_password;
}

public void setCred_password(String cred_password) {
    this.cred_password = cred_password;
}

public String getCred_token() {
    return cred_token;
}

public void setCred_token(String cred_token) {
    this.cred_token = cred_token;
}

      

        
        
        
      

    

}

Below is my resource class

public class ValidateUser {
@POST
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
public String validateUser(Credentials credentials) {
    System.out.println("Going to validate the user" + credentials);
    String username = credentials.getCred_user_name();
    String password = credentials.getCred_password();
    CredentialsAccessor ca = new CredentialsAccessor();
    long count = 0;
    count = ca.authenticateUser(username, password);
    if (count > 0) {
        JSONObject jObject = new JSONObject();
        try {
            jObject.put("valid", "true");
            return jObject.toString();
        } catch (JSONException e) {
            e.printStackTrace();
            return "{'valid':'error'}";
        }
    } else {
        JSONObject jObject = new JSONObject();
        try {
            jObject.put("valid", "false");
            return jObject.toString();
        } catch (JSONException e) {
            e.printStackTrace();
            return "{'valid':'error'}";
        }
    }
}

      

        
        
        
      

    

}

See maven dependencies here

I ensured that in the RESTClient I will specify the content type as Content-Type: application / json

See RESTClient

Below is my web.xml

But even then, I get the error " Getting HTTP Status 415 - Unsupported Media

Can you picture where I am going wrong?