server request and response

public class ServerRequest {

    @SerializedName("operation")
    @Expose
    private String operation;

    @SerializedName("studentModel")
    @Expose
    private StudentModel studentModel;

    public void setOperation(String operation) {
        this.operation = operation;
    }

    public void setStudentModel(StudentModel studentModel) {
        this.studentModel = studentModel;
    }
}

public class ServerResponse {

    private String result;
    private String message;
    private StudentModel studentModel;

    public String getResult() {
        return result;
    }

    public String getMessage() {
        return message;
    }

    public StudentModel getStudentModel() {
        return studentModel;
    }

}