Frank Asseg

This might be the end of captchas in the not-so-distant future: This machine kills CAPTCHAs

I want to describe a way to secure a JAX-RS webapp using HTTP Basic-Auth in Apache Tomcat with a JDBCRealm. There’s always the question of how to secure a RESTful webapp without breaking one of the big REST paradigms: Do not maintain session state on the server side! But because I was so used to handling user contexts via sessions, I was forced to rethink. One way to go is HTTP-Basic Auth a s described in RFC2617. But one has to go through some steps in order to marry a domain model of users and groups to Tomcat’s authentication service,...

Today the Apache Software Foundation declared it’s resignation from the JCP most important device, the Executive Committee, mainly because of Oracle’s attitude towards the Open Source community. The Java Community Process is the mechanism by which new features get added to the Java Language Specification and the Executive Committee is the desicion maker on every level of this process. They get to decide which specification gets to be approved for development. It reviews the early drafts of the specs together with the community, and decides when a new draft is ready to be released to the public and they have...

On his blog Stephen Gennard shows how to use the Unsafe class from Sun to manipulate objects on the heap directly. With this trick it’s possible to change memory addresses or contents of any object. Only the JVM has to be started in a different manner for this to work, since permissions to access the restricted classes is needed. The “-Xbootclasspath/p:” option tells the JVM to prepend the class to the bootloader, so that it can access the restricted sun.misc.Unsafe class. Check out Fiddling with the JVM on Gennard’s blog.

Google’s new web image format WebP (say: weppy) could be the next corpse in the sea of failed JPEG replacements. WebP is based on Google’s own open source WebM Project for encoding and decoding video. Like JPEG or PNG WebP features a lossy compression. WebP encoded images are up to 40% smaller than a comparable JPEG file. The WebP images have their own RIFF container so that metadata can be easily added and could be easily upgraded to hold more meta information in the future. In a comparison google found that the compression of WebP gains more advantage over the...

Let me explain the problem first: When retreiving Objects from Hibernate it is vital that the Session stays open if collections are to be fetched later. This is because Hibernate uses proxies for collections which only fetch data from the DB if it is actually needed.

This is my lightweight blogging web application built on the following stack:

Oh, the times we live in! James Gosling announced on his blog that he left Oracle. After working 25 years for Sun Microsytems leaving soon after Oracle’s aqcuisition, the man credited with the invention of the Java Programming Language writes that he will now take a break before looking for a new project. Losing the third big name after Scott McNealy and Jonathan Schwartz might indicate that Oracle has trouble keeping Sun’s former staff. In my opinion the negative effect this would have on the Java language is not very grave, because of the JCP and the transparency of the...

When I recently tried to have a annotated web service authorize against spring-security using @Secured annotations I ran into some trouble. Let’s consider this class:

So here is what recently occured to me. It’s all neatly sorted around humans. Cars in parking lots, books on shelves, contents in a cupboard. From a thermodynamical view just staying alive means you have to sort your body by applying work to transfer energy from the outside i.e. eat. Just look at the Action Potential as a nice illustration of how organisms have need for sorting ions. So if all life is constantly sorting and life begets life, does that mean life is a poorly implemented recursive sorting algorithm?