Made more progress on the Java application (learning all the time):

• Input text box now displays line-breaks correctly. Previously, incoming linebreaks (u000d) were ignored (presumably because of the platform). I now convert them to u00du00a (=\r\n), which result in real line breaks in the edit control; the processing code also now looks for that combination. It remains to be seen whether, on other platforms, these show up as double line breaks.
• The file opening code is now able to search for sigla and automatically populate the sigla table with values. It does this by searching for anything ending in ".txt" delimited by whitespace, which seems to work reliably for our data set.
• All blank lines in the base text are now correctly detected, and shown in the output as an empty <lem> tag, with a comment that the line is missing in the base text.

The final stage is to parse out all the witness readings and create <rdg> tags. To do that, I'll have to split each line based on siglum+whitespace+comma, to get each reading into a separate string, then read the string up to the first siglum to get the reading, and the subsequent sigla to go with it.