Re: NPE in parser->getDOMImplementation() with CNI

[Sam Ruby <rubys@intertwingly.net>]

Andrew Haley wrote:
> Sam Ruby wrote:
>> Andrew Haley wrote:
>>> Mark Wielaard wrote:
>>>> On Sun, 2009-06-21 at 16:46 +0100, Andrew Haley wrote:
>>>>> Sam Ruby wrote:
>>>>>> I'm trying to develop a JAXP implementation using CNI, but I get a
>>>>>> NullPointerException when I try to get a DOMImplementation.  I've
>>>>>> attached a small script (tested on Ubuntu 9.04) which demonstrates the
>>>>>> problem.
>>>>>>
>>>>>> Any help would be appreciated.
>>>>> Congratulations on this excellent test case.  Next time I want to tell
>>>>> people how to do it right, I'll point them at your posting.
>>>>>
>>>>> However, I get
>>>>>
>>>>>  $ sh ~/testdomimpl.sh
>>>>> gnu.xml.dom.DomDocumentBuilderFactory@160ecdad
>>>>> gnu.xml.dom.DomDocumentBuilder@15ffbc45
>>>>> gnu.xml.dom.DomImpl@15ef0ee5
>>>>>
>>>>> gnu.xml.dom.DomDocumentBuilderFactory@2df0bea7
>>>>> gnu.xml.dom.DomDocumentBuilder@2de03d5f
>>>>> gnu.xml.dom.DomImpl@2dd0bfdf
>>>>>  $ gcj --version
>>>>> gcj (GCC) 4.4.0 20090307 (Red Hat 4.4.0-0.23)
>>>> I get the same with that version of gcj.
>>>> But on an older gcj installation:
>>>> gcj (Debian 4.3.2-2) 4.3.2
>>>>
>>>> gnu.xml.dom.DomDocumentBuilderFactory@6992f029
>>>> gnu.xml.dom.DomDocumentBuilder@647a3539
>>>> gnu.xml.dom.DomImpl@64826fa9
>>>>
>>>> gnu.xml.dom.DomDocumentBuilderFactory@17d5dffb
>>>> gnu.xml.dom.DomDocumentBuilder@12bcf52b
>>>> java.lang.NullPointerException
>>>>    at java.io.PrintStream.println(PrintStream.java:473)
>>> I found the problem.
>>>
>>> There is an implementation of jaxp in /usr/share/java/jaxp-1.3.jar and
>>> another in /usr/lib/libgcj.so.90.  They are not the same version, and
>>> they are not compatible.
>>>
>>> If you link against /usr/lib/libgcj.so.90 then you must compile against
>>> the version of jaxp in that library.
>>>
>>> Do this:
>>>
>>> gcjh -cp /usr/share/java/libgcj.jar -d headers \
>>>   org.w3c.dom.DOMImplementation \
>>>   javax.xml.parsers.DocumentBuilder \
>>>   javax.xml.parsers.DocumentBuilderFactory
>> I still see the problem.  Even after I apt-get remove libjaxp1.3-java-gcj.
> 
> The problem is not libjaxp1.3-java-gcj, it's libjaxp1.3-java

Bingo!  apt-get remove libjaxp1.3-java... problem solved!  Thanks!

- Sam Ruby