I've been using Eclipse 4.4.2 with MercurialEclipse plug-in for a while, and everything worked fine. However, when I just tried to install it in Eclipse 4.5.0, an error is thrown very early in the process of installation. The error message is as follows:
com.sun.org.apache.xerces.internal.impl.io.MalformedByteSequenceException: Invalid byte 1 of 1-byte UTF-8 sequence.
Plugin: org.eclipse.equinox.p2.updatesite 1.0.500.v20150423-1455
Message: Error reading update site http://mercurialeclipse.eclipselabs.org.codespot.com/hg.wiki/update_site/stable.
The version of
plug-in in Eclipse 4.4.2 is
, and the version in Eclipse 4.5.0 is
. The MercurialEclipse site is located at  and is a legacy site.xml-based update site.
One issue here is that the problem is not always reproducible. In my case the error happens all the time, but my colleague does not ever get it despite using the same Eclipse version. Finally, some folks have apparently managed to get rid of it by appending a slash to the update site url  or using a sibling update site that is produced in a similar fashion . Btw, I've also left a reply on that Stackoverflow question.
To be clear, I think MercurialEclipse project should migrate to p2 update sites, but this specific issue seems to be a bug that was likely introduced between p2.updatesite 1.0.400 and 1.0.500. Hence, two questions:
Â- Is it a known issue or something that sounds straightforward to guess?
Â- Do you have any ideas what I should look at to make it more reproducible? System language settings, specific installed plug-ins, something else?