Unicode bug fix cleanup

@airbnb/di 

We have a bug that all the non-ascii unicode characters  in our log files are converted into "?" since 08/05/2014. The problem was that when we convert String from/to byte[], we did not specify the character set  (Charset) in our code. When the default Charset is not UTF-8, the non-ascii unicode characters are not handled correctly. 
Sorry. I do not understand the issue ... What is the format convention here?