Oscar Westra van Holthe - Kind

Sparse writing

This page lists some of the things I've written. There is a hiatus due to stuff I blogged about at 42 (a previous employer). Otherwise, the things I consider most important to write about will (eventually) find a place here.

Persistence API's - JPA vs. JDO

An overview of differences between JDO and JPA, and why JPA is the better choice.

Read more…

Implementing equals and hashCode

A somewhat old subject, especially considering two of the referenced pages are from 2002. But nevertheless still often done wrong today. Also explains how to implement equals and hashCode() for persistent entities (EJB / JPA @Entity classes).

Read more…

Authentication (a few notes)

Authentication, or verification of who a user is, is a key element in enforcing access controls. While application servers offer a great deal, and much documentation can be found on the subject, it is crucial to keep a few things in mind.

Read more…

RESTful web services & applications

Why I'd use the REST philosophy for web applications, and not for web services.

Read more…


In order to write (web) applications that a user can trust, logging is essential. In this short article I explain a practical view to logging.

Read more…

Web framework abstractions

A simple piece about abstractions in frameworks for web applications. Gives a comprehensive account of the options available.

Read more…

Access Controls

An explanation on how to go beyond simple role based declarative security. As one of my older pieces it's quite dense, but it's reasoning I still find persuasive.

Read more…