piątek, 17 października 2014

Spring component-scan classpath pitfall

There is one non-intuitive behavior with Spring's component-scan - it works on _current_ classpath. For example:

Project A

context-a.xml:

    <component-scan package="x">


Project B

context-a.xml:

    <import resource="classpath:/a.xml" /> 

    <component-scan package="x.y">


This will load all components from  package "x.y" already at <import> tag.  It can lead to very strange errors in bigger projects (sudden appearance of "NoSuchBeanDefinitionException: No qualifying bean of type" errors) and  trying to cherry-pick used imports/components might be hard or even impossible.
There is similar issue with integration tests - Spring will scan all classes in package, including test files, for components. If you are using inner static classes to override context configuration spring will pick up all of them. And that problem might propagate if you are reusing test support code (<classifier>tests</classifier>). Lucky this one is easy to deal with: it is possible to filter it out:
<context:component-scan base-package="my.package" >
        <context:exclude-filter type="annotation" expression="org.springframework.context.annotation.Configuration" />
        <context:exclude-filter type="regex" expression=".*IT" />
        <context:exclude-filter type="regex" expression=".*Test" />
</context:component-scan>

piątek, 7 czerwca 2013

Unable to find a public constructor for class org.jboss.resteasy.core.AsynchronousDispatcher

Takim wspaniałym komunikatem wita nas próba zdeployowania prostej aplikacji używającej RestEasy na JBossa 7.1. Obejście jest proste ale mało wygodne. Trzeba wyłączyć automatyczne skanowanie w web.xml:
<context-param>
    <param-name>resteasy.scan</param-name>
    <param-value>false</param-value>
</context-param>
I ręcznie podać usługi np.:
<context-param>
    <param-name>resteasy.resources</param-name>
    <param-value>net.purevirtual.web.MyService</param-value>
</context-param>
Inne opcje konfiguracyjne są w dokumentacji . A skoro już jesteśmy przy temacie AS: http://stackoverflow.com/questions/12511192/replaced-with-quot-when-loading-page Tak, nie ma to jak wersja serwera aplikacji z dopiskiem Final, która od czasu do czasu kompletnie rozwala serwowany kod JavaScript

piątek, 22 lutego 2013

File extensions recognized by Drools

Just in case anybody else needs it. I didn't know why KieRepository didn't pick up one file, of course I had a typo in file extension.

typeextensions
Drools Rule Language.drl
Drools XML Rule Language.xdrl
Drools DSL.dsl
Drools DSL Rule.dslr
Drools Rule Flow Language.rf
jBPM BPMN2 Language.bpmn, .bpmn2
Decision Table.xls
Binary Package.pkg
Drools Business Rule Language.brl
Change Set.xcs
XSD.xsd
Predictive Model Markup Language.pmml
Knowledge Descriptor.descr
List is copied from org.drools.builder.ResourceType.

niedziela, 14 października 2012

WINE oneliners

fixme:d3dcompiler:D3DCompile data data_size 424, filename "memory", defines (nil), include 0x32ed50, entrypoint "VShad",
is solved by
winetricks d3dcompiler_43

Switching to multi-arch on NVidia amd64 systems

The following packages have unmet dependencies:
 nvidia-glx : Depends: xserver-xorg-video-nvidia (= 304.60-1) but it is not going to be installed
              Recommends: nvidia-settings
              Recommends: libgl1-nvidia-glx-i386 but it is not installable
              Conflicts: nvidia-glx:i386 but 304.60-1 is to be installed

or
"err:module:load_builtin_dll failed to load .so lib for builtin L"opengl32.dll": libGL.so.1: cannot open shared object file: No such file or directory"
"Direct rendering is disabled, most likely your OpenGL drivers haven't been installed correctly"
is fixed by
sudo dpkg --add-architecture i386
sudo apt-get update
#remove ALL nvidia related packages
dpkg -l *nvidia* |cut -f 3 -d ' '|grep -v any|grep nvidia|xargs sudo apt-get purge -y
#install the driver just for amd64
sudo apt-get install nvidia-glx
#install the openGl libs for both archs
sudo apt-get install libgl1-nvidia-glx libgl1-nvidia-glx:i386

czwartek, 14 czerwca 2012

Java Classes Fun Fact

java.lang.NoClassDefFoundError can be caused by runtime exception (i.e. NPE) in static initialization blocks or even variable initialization of class you are trying to use.

czwartek, 9 lutego 2012

Reading outlook .msg files under Linux

Got an email in format unreadable for your mail reader?
I always forget that there is great tool for doing just that: http://code.google.com/p/ruby-msg/

sobota, 7 stycznia 2012

Valgrind - "client switching stacks"

If you ever start to receiving following warning from Valgrind:
Warning: client switching stacks?
Followed by many error messages like "Invalid read/write" containing a note: "Address  is on thread 1's stack" then the cause is very simple. You are just allocating too large variables on stack - in my case I had too large array, as local variable, in one of functions. If you can't or don't want to use heap it is possible to tune valgrind with "--max-stackframe" parameter i.e.
valgrind --max-stackframe=10485760 ./a.out
This will prevent false positive detection  of stack switching up to 10MB.

One additional, much more obvious tip, use "-fno-inline" when building C++ binaries for use with valgrind, otherwise there won't be line numbers in stacktraces for any template functions.