Problem with Java

What is the problem?

This site uses Java applets to solve the sudokus. On Januari 14th 2014 a Java update was released which (by default) only executes Java applets that adhere to stricter demands than before. Unfortunately, one of these demands is that the applets are digitally signed using a certificate that has been issued by a CA (Certificcation Authority). Unfortunately, because this involves annual costs that I am not prepared to pay (about 100 euros each year).

How and when will this be solved?

I am now replacing the Java code that is used. The first sudoku type has been replaced by a JavaScript version. Most of the other sudokus will be replaced before February 14th, 2014.

Can the current Java sudoku solvers be used?

It is possible to allow Java applets on to be executed (after a security warning message). You can do this by adding this site as an exceptiion in the Java configuration. The next page, which opens in a separate window, explains how to do this.


I want to make some things clear to avoid misunderstandings:

  1. I use the word "unfortunately" when I mention the demand that Java applets are signed digitally. By this, I mean that (because of the costs that are involved) I now need to switch to an alternative. By signing the applets, it is clear who is responsible for the applet. Someone who wishes to do harm by modifying the applet can only do this by signing the applet himself/herself with a valid certificate. This makes it more difficult, because he/she will not want to do this with a certifcate of himself/herself.
  2. I do not intend to advise you to delay Java updates. These updates contain solutions for (a.o.) security issues in Java. These solutions increase security of your computer.
  3. I was surprised by this Java update. It was clear that modifications were being made to security settings of Java. Due to personal circumstances I was not able to actively follow the changes and find out what the future plans for Java are. Looking at applets on other sites, I can tell that I am not the only one that has not anticipated this problem. The Java developers have not made a secret of this change. They have not been able to inform all Java developers oof these changes before the update was released.

©2014, Renze de Waal.