RFR 8009581: Xpathexception does not honor initcause()

[Aleksej Efimov]

Hi all,

Can I have a reviews for the following change:
http://cr.openjdk.java.net/~dmeetry/8009581/webrev.0/ 
<http://cr.openjdk.java.net/%7Edmeetry/8009581/webrev.0/>

Summary:
There is an erroneous behavior in 'initCause' method of 
javax.xml.xpath.XPathException class.
Lets look at the following situation:
XPathException is created with 'XPathException(String )' constructor and 
then the cause is initialized with 'initCause' method. Such 
initialization sequence of actions isn't restricted by XPathException 
[1] and Throwable [2] docs.
After that a cause is retrieved by 'getCause()' method: this call 
returns incorrect cause = 'null'. It should return the same cause as was 
used in 'initCause'.  And this is the erroneous behavior.

Suggested fix (with regression test) is applicable both for JDK 8 and 7.

Regards,
-Aleksej


[1] 
http://download.java.net/jdk8/docs/api/javax/xml/xpath/XPathException.html
[2] 
http://download.java.net/jdk8/docs/api/java/lang/Throwable.html#initCause(java.lang.Throwable) 
<http://download.java.net/jdk8/docs/api/java/lang/Throwable.html#initCause%28java.lang.Throwable%29>
[3] http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8009581