And this is why you test and fix stuff

There are a couple of interesting messages featured in the Forums section that speak to an experience surely all of us have had: people using our software in unexpected ways. It's so easy to develop your APIs or applications with certain use cases in mind that you don't anticipate and handle uses of your stuff that, while perhaps syntactically correct, falls on its face when run.

For example, let's say you make an assumption about appropriate font sizes for a small screen, based on sample text. Well, are you accounting for other languages? Other character sets? Following up in http://forums.java.net/jive/thread.jspa?messageID=337596&tstart=0#337596, a long-running thread about bundling fonts into LWUIT apps, "browneye man" explains a problem using Chinese in a LWUIT app:

I've noticed that on my Nokia S60 phone, there are other applications that can control the font size at a much finer scale. I'm guessing that it is the Java VM that is putting the limit on font control. Can anyone comment on that? My application is a Chinese ebook reader. There are 2500 frequently used Chinese characters in the language. Because of the complexity of Chinese Characters, a font size that is too small is not readable. So if you imagine 2500 medium sized bitmapped Chinese Characters included with my jar, it takes too much space and too long to load.

Pointing out another edge case, ranboii realizes that JAXB can generate Illegal XML characters:

Apparently there are some XML characters that are illegal to have in the content area of an XML document, and there is no way to "escape" them to make them legal. For example, 0x1F is an illegal character. So if a java object happens to contain that character (which is legal in a Java string), JAXB will quietly generate invalid XML! Then when we try to unmarshal that XML back into an object, an exception is thrown. This means that the ability of JAXB to correctly marshal and unmarshal an object depends on what data happens to be in the fields of the object! That doesn't seem like a very safe or general solution.

Fortunately, LWUIT and JAXB are open-source (both are GPL), so if either or both of these are genuine bugs, they're likely to get fixed.