This can be set using the JVM's system property 'file.encoding'. See the manual for more information.
Yes. Please see the manual for more information.
JSCover reuses JSCoverage's regression tests (see InstrumentAndHighlightRegressionTest) and has added a suite of unit, integration and acceptance tests which give a fairly high degree of coverage (~97% line, ~95% branch). JavaScript tests have also been added (using Jasmine) and JSCover is used to check JavaScript coverage (see HtmlUnitJSTest).
All bugs are corrected by first writing failing test to ensure no regression errors occur.
Try:
Yes.
Not necessarily. Usually the worst that could happen is that an instrumentation line has been missed. See the manual for more information.
Also see the JSCoverage FAQ