j2se/src/share/classes/sun/tools/jconsole/VMPanel.java line 568 has a non-ASCII character (right single quote):
// Set the first enabled tab in the tab's list
This can cause problems if someone is trying to compile JDK sources and is using -encoding US-ASCII or UTF-8. (The character appears to be encoded in ISO-8859-1.) As far as I can tell this is the only non-ASCII character in j2se/src/share/classes/**/*.java.
$ svn -v stat j2se/src/share/classes/sun/tools/jconsole/VMPanel.java
64 56 bnoble j2se/src/share/classes/sun/tools/jconsole/VMPanel.java