An annotation that indicates the version number until a member or a type should be present. Basically, if Gson is created with a version number that is equal to or exceeds the value stored in the Until annotation then the field will be ignored from the JSON output. This annotation is useful to manage versioning of your JSON classes for a web-service.

This annotation has no effect unless you build com.google.gson.Gson with a GsonBuilder and invoke the GsonBuilder#setVersion(double) method.

Here is an example of how this annotation is meant to be used:

public class User {
  private String firstName;
  private String lastName;
  @Until(1.1) private String emailAddress;
  @Until(1.1) private String password;
}

If you created Gson with new Gson(), the toJson() and fromJson() methods will use all the fields for serialization and deserialization. However, if you created Gson with Gson gson = new GsonBuilder().setVersion(1.2).create() then the toJson() and fromJson() methods of Gson will exclude the emailAddress and password fields from the example above, because the version number passed to the GsonBuilder, 1.2, exceeds the version number set on the Until annotation, 1.1, for those fields.