This is the screen resolution. This resolution was the "Gold Standard" for mid-range phones in the mid-2000s.
Not all Java apps work well on small screens. Here are the best specific versions for the "Extra Quality" experience: opera mini java 240x320 fixed extra quality
Finding a clean copy of can be tricky. The original file-hosting sites (RapidShare, MediaFire links from 2008) are mostly dead. This is the screen resolution
The resolution was the industry standard for mid-to-high-end Java-enabled (J2ME) phones. Because the aspect ratio was so common, developers could perfectly calibrate the UI of Opera Mini. opera mini java 240x320 fixed extra quality