blojsom's back-end uses the filesystem where categories are directories and entries are simply files within those directories.
After you've created your new category, look into giving your category a more descriptive name.
Creating hierarchical categories in the administration console
From the administration console, select "Categories" tab. To add a new category off an existing category, select the proper parent category from the existing categories.
As a concrete example, let's say you want to create a "Swing" category underneath your "Java" category. The category name would be as follows and in the following figure.
Creating hierarchical categories from the command-line
If you have access to the system on which blojsom is running, simply change to the blog-home directory for the particular user you want to create a new category for, navigate to the particular directory where the new category should be created and finally, create a new directory. This can be done from the command-line or from a directory tool such as the Windows Explorer or Apple Finder.
As a concrete example, let's say you've got the following directory structure for a user on your blog.
Now, if you want to create a new category swing underneath the java category, simply navigate to the /blog/david/java directory and create the swing directory. That's it! That blog now has a new category. The directory structure would now look as follows.
