Probably due to missing author field in, e.g. Standards.
null
java.lang.NullPointerException
at textools.commands.MinifyBibtexAuthors.minifyDatabase(MinifyBibtexAuthors.java:45)
at textools.commands.MinifyBibtexAuthors.execute(MinifyBibtexAuthors.java:32)
at textools.Main.main(Main.java:37)
Probably due to missing author field in, e.g. Standards.