Gson deserialisation generates NULL value

Question

I was trying to read and convert a JSON file to an array but getting null values from the array after reading the JSON file. I am using the default constructor for my Ship

Answer 1

Your Gson mapping does not match the given JSON. By default, Gson maps JSON properties to their appropriate fields in the target mapping by exact name. Take a look at:

"idmessage":"27301"

and

private String IdMessage

The property name case and the field name case do not match. What you need is map your JSON correctly. Either:

private String idmessage

or by overriding the name match (and that's more appropriate for the Java naming conventions):

@SerializedName("idmessage")
private String idMessage;

Note one field per line. This is required in order to annotated each field separately. Or, if possible, use camelCase both in Java and JSON.