Meaningful error message from IBM WebSphere

Seeing this on your WebSphere application server startup?

00000000 ContainerHelp E   WSVR0501E: Error creating component com.ibm.ws.cluster.runtime.ProcessRuntimeImpl
java.lang.NoClassDefFoundError: com.ibm.websphere.cluster.topography.DescriptionManagerFactory (initialization failure)
        at java.lang.J9VMInternals.initialize(J9VMInternals.java:140)
        at com.ibm.ws.cluster.runtime.ProcessRuntimeImpl.initialize(ProcessRuntimeImpl.java:366)
        at com.ibm.ws.runtime.component.ContainerHelper.initWsComponent(ContainerHelper.java:1166)
        at com.ibm.ws.runtime.component.ContainerHelper.initializeComponent(ContainerHelper.java:1073)
        at com.ibm.ws.runtime.component.ContainerHelper.initializeComponents(ContainerHelper.java:874)
        at com.ibm.ws.runtime.component.ContainerImpl.initializeComponents(ContainerImpl.java:780)
        at com.ibm.ws.runtime.component.ContainerImpl.initializeComponents(ContainerImpl.java:754)
        at com.ibm.ws.runtime.component.ServerImpl.initialize(ServerImpl.java:350)
        at com.ibm.ws.runtime.WsServerImpl.bootServerContainer(WsServerImpl.java:280)
        at com.ibm.ws.runtime.WsServerImpl.start(WsServerImpl.java:214)
        at com.ibm.ws.runtime.WsServerImpl.main(WsServerImpl.java:666)
        at com.ibm.ws.runtime.WsServer.main(WsServer.java:59)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:45)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37)
        at java.lang.reflect.Method.invoke(Method.java:599)
        at com.ibm.wsspi.bootstrap.WSLauncher.launchMain(WSLauncher.java:213)
        at com.ibm.wsspi.bootstrap.WSLauncher.main(WSLauncher.java:93)
        at com.ibm.wsspi.bootstrap.WSLauncher.run(WSLauncher.java:74)
        at org.eclipse.core.internal.runtime.PlatformActivator$1.run(PlatformActivator.java:78)
        at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:92)
        at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:68)
        at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:400)
        at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:177)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:45)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37)
        at java.lang.reflect.Method.invoke(Method.java:599)
        at org.eclipse.core.launcher.Main.invokeFramework(Main.java:340)
        at org.eclipse.core.launcher.Main.basicRun(Main.java:282)
        at org.eclipse.core.launcher.Main.run(Main.java:981)
        at com.ibm.wsspi.bootstrap.WSPreLauncher.launchEclipse(WSPreLauncher.java:330)
        at com.ibm.wsspi.bootstrap.WSPreLauncher.main(WSPreLauncher.java:108)
Caused by: java.lang.IllegalStateException: java.lang.NullPointerException
        at com.ibm.ws.util.ImplFactory.loadImplFromClass(ImplFactory.java:354)
        at com.ibm.ws.util.ImplFactory.loadImplFromKey(ImplFactory.java:328)
        at com.ibm.ws.util.ImplFactory.loadImplFromKey(ImplFactory.java:332)
        at com.ibm.ws.wlm.Factory$4.run(Factory.java:141)
        at java.security.AccessController.doPrivileged(AccessController.java:251)
        at com.ibm.ws.wlm.Factory.loadImpl(Factory.java:139)
        at com.ibm.websphere.cluster.topography.DescriptionManagerFactory.(DescriptionManagerFactory.java:50)
        at java.lang.J9VMInternals.initializeImpl(Native Method)
        at java.lang.J9VMInternals.initialize(J9VMInternals.java:200)
        at com.ibm.ws.cluster.service.ClusterManagementImpl.(ClusterManagementImpl.java:119)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:45)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:39)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:515)
        at com.ibm.wsspi.cluster.ClusterManagementFactory.(ClusterManagementFactory.java:62)
        at java.lang.J9VMInternals.initializeImpl(Native Method)
        at java.lang.J9VMInternals.initialize(J9VMInternals.java:200)
        at com.ibm.ws.cluster.runtime.WLMDiagnosticModule.ffdcDumpDefaultClusterManagement(WLMDiagnosticModule.java:422)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:45)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37)
        at java.lang.reflect.Method.invoke(Method.java:599)
        at com.ibm.ws.ffdc.DiagnosticModule.getDataForDirective(DiagnosticModule.java:305)
        at com.ibm.ws.ffdc.DiagnosticModule.getDataForDirectives(DiagnosticModule.java:279)
        at com.ibm.ws.ffdc.DiagnosticModule.dumpComponentData(DiagnosticModule.java:144)
        at com.ibm.ws.ffdc.impl.DMAdapter.processDM(DMAdapter.java:123)
        at com.ibm.ws.ffdc.impl.DMAdapter.formatTo(DMAdapter.java:114)
        at com.ibm.ffdc.util.provider.IncidentLogger.writeIncidentTo(IncidentLogger.java:63)
        at com.ibm.ws.ffdc.impl.FfdcProvider.logIncident(FfdcProvider.java:135)
        at com.ibm.ws.ffdc.impl.FfdcProvider.logIncident(FfdcProvider.java:92)
        at com.ibm.ffdc.util.provider.FfdcProvider.log(FfdcProvider.java:232)
        at com.ibm.ws.ffdc.impl.FfdcProvider.log(FfdcProvider.java:100)
        at com.ibm.ffdc.util.provider.IncidentEntry.log(IncidentEntry.java:96)
        at com.ibm.ffdc.util.provider.Ffdc.log(Ffdc.java:90)
        at com.ibm.ws.ffdc.FFDCFilter.processException(FFDCFilter.java:114)
        at com.ibm.ws.cluster.ProcessProperties.(ProcessProperties.java:281)
        at com.ibm.ws.cluster.ProcessProperties.(ProcessProperties.java:234)
        at java.lang.J9VMInternals.initializeImpl(Native Method)
        at java.lang.J9VMInternals.initialize(J9VMInternals.java:200)
        at com.ibm.ws.cluster.runtime.ProcessRuntimeImpl.initialize(ProcessRuntimeImpl.java:307)
        ... 31 more
Caused by: java.lang.NullPointerException
        at com.ibm.ws.cluster.WLMCustomPropertyUtility.getBBCallbacksEnableWLMThreads(WLMCustomPropertyUtility.java:384)
        at com.ibm.ws.cluster.propagation.bulletinboard.BBDescriptionManager.(BBDescriptionManager.java:165)
        at java.lang.J9VMInternals.newInstanceImpl(Native Method)
        at java.lang.Class.newInstance(Class.java:1325)
        at com.ibm.ws.util.ImplFactory.loadImplFromClass(ImplFactory.java:349)
        ... 70 more

This should probably mean that your PC's hostname couldn't be resolved.

[Ubuntu] Reverting upgrade from thir party PPA

History
I got new hardware for my PC at work (i3-2100 with integrated Intel HD Graphics 2000). My Ubuntu 10.10 installed didn't feature proper drivers for this GPU, but some folks over the Web advised to add xorg-edgers PPA which hosts bleeding edge version of Xorg and drivers.
It's worth saying that I my Xorg rejected to extend my desktop to both monitors after this upgrade :)

Task
So I started searching for the way to revert this update :)

Solution
Finally Synaptic saved me! I'll appreciate if somebody will teach me how to do the same from command line.

So:

1. open Synaptic
2. select group by Origin (bottom left corner)
3. in the list on the left find the source repo you did the upgrade from
4. now select installed packages (from this repo) one by one and for each to Package - Force Version... (Ctrl + E)

After that you could remove the PPA and don't do that again :)
Some more helpful info is available at https://help.ubuntu.com/community/CleanUpgrade

Some more useful Skype scripts

I was going to write a script to mute\unmute Skype during a call, but I was unable to find DBus API documentation for Skype (I would be very pleased if you share a link or a document if you have one). Today I've found the script I need along with few more useful scripts:

• Toggle Skype main window I wrote earlier in my blog
• Answer\Hangup a call page in Russian
• Mute (or Answer) Skype Calls with BT Headset Button in Linux 

All these stuff could be easily bound to a hotkey depending on environment you're using.
Happy Skyping :)

Post SVN changelist to ReviewBoard (using post-review tool)

Yeah, this will work out of the box only for Unix systems. But I have no worries about that :)

$ svn stat --changelist "changelist name" | tail -n +3 | awk '{print $NF}' | grep -v 'gwt\.xml$' | xargs post-review -o

Here I post for review changelist named "changelist name" excluding GWT module descriptor files (*.gwt.xml), which a not to be commited and opens browser window with newly created review request.
As for locally modified files that are under SVN control, I usually move those that shouldn't be commit to separate changelist (named "no-commit"). Yes, I'm delighted with changelists support in IntelliJ IDEA! :)

How to restore Linux loader after installing Windows without Live-CD

Often having both Linux and Windows installed on the same PC I face trouble when after reinstalling Windows my Linux loader (GRUB\LILO\whatever) got erased with nasty one from M$. Before I always had to look up some live-CD distro to boot and restore GRUB. Today I was too lazy to do that - I had no suitable CD (or maybe it's time to throw away my CD drive) and after a quick look through the web I've found GRUB4DOS. So what magic does it provide? Here is the trick - GRUB4DOS allows you to install it from withing your running Windows instance, it boots up a GRUB-like stuff where you can select another partition to boot from. Basically you then boot to your broken GRUB record, then boot up your Linux distro and then having complete environment you just restore your broken GRUB MBR record. Easy, ha! To install the GRUB4DOS we don't even need to perform any dangerous manipulations with MBR. You just download grub4dos or grubinst package from http://sourceforge.net/projects/grub4dos/files/, copy grbldr from the package to your system drive root (e.g. C:\grbldr) and add following line to boot.ini:

C:\GRBLDR="GRUB4DOS"

Now you just need to reboot the PC, boot your Linux distro and reinstall GRUB On my ArchLinux I did the following:

$ sudo grub-install --root-directory=/ \(hd0\)

This installed GRUB to the MBR of my first hard drive and put staging files under /boot/grub directory.