Should we follow the Java method naming conventions then?

Thanks. Approved.

Looks OK. Will approve.

You should use

import static org.junit.Assert.assertArrayEquals;

You are returning a string. Why not return

int [] 

In addition to letters, digits and some punctuation, there are some special service codes, the most notorious of those is the international distress signal SOS (that was first issued by Titanic), that is coded as ···−−−···. These special codes are treated as single special characters, and usually are transmitted as separate words.