If you have a *.java in a project set to use UTF-8 acc. to FileEncodingQuery, and you call wc.getTreeMaker().Literal("čau") and insert the result somewhere in the document, you will "\u010dau" even though the source file is capable of storing the character unescaped. Unicode escapes should be used only when the javac encoding could not otherwise represent the character.
This old bug may not be relevant anymore. If you can still reproduce it in 8.2 development builds please reopen this issue.
Thanks for your cooperation,
NetBeans IDE 8.2 Release Boss