Elicpse CDT thinks it's broken

Question

I'm using Eclipse for some embedded development and recently is started to give me these errors every time I save a file or do a build. It's annoying but for the most part it doesn't seem to be causing any problems (It even still highlights warnings/errors int the source. What's going on here?

Plug-in org.eclipse.cdt.cross.arm.gnu was unable to load class 
org.eclipse.cdt.managedbuilder.internal.scannerconfig.DefaultGnuWinScannerInfoCollector.

Plug-in org.eclipse.cdt.cross.arm.gnu was unable to load class  
org.eclipse.cdt.managedbuilder.internal.scannerconfig.ManagedGCCScannerInfoConsoleParser

Answer 1

It looks like the eclipse wiki FAQ says

The most likely reason is that an exception was thrown in the static initializer for a class declared by the offending plug-in. Check the .log file to see whether that indeed happened.
The Eclipse Platform loader will not load a plug-in when exceptions are thrown during the initialization of the Java classes that make up the plug-in.

Another common reason for this error is the lack of an appropriate constructor for the class being loaded. Most classes declared in extension points must have a public zero-argument constructor. Check the extension point documentation to see what constructor is required for the classes that you declare in an extension.

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If the problem only occurs when deploying a packaged plug-in (i.e., when it is not started in a runtime workbench via PDE) it is usually a good idea to check the Bundle-ClassPath attribute in the MANIFEST.MF file.
The JAR file that contains the plug-in classes must be listed in the Bundle-ClassPath. Even if the plug-in's proper classes are all listed, class loading may still fail because a .class file may contain references to other classes that cannot be resolved at runtime. In this case, the missing classes need to be identified (usually by looking at the import statements of the problematic class) and the necessary entries need to be added to the Bundle-ClassPath. If additional JAR files are required, those JARs also need to be listed in the build.properties file so that they are included when the plug-in is packaged.

(See this thread as an illustration of that last point)

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So, for instance, in this thread, for another issue back in eclipse3.0 time:

The plugin.xml file specifies "org.eclipse.core.runtime.compatablity" as a required plugin. However, I am using Eclipse Version 3.0.1 and should be using "org.eclipse.core.runtime_3.0.1".

Solution:

Replace the line in the Plugin.xml

<import plugin="org.eclipse.core.runtime.compatability"/>

with

<import plugin="org.eclipse.core.runtime"/>

Answer 2

VonC is right -- with a fair bit of detail on what might go wrong with class loading...

In this case, your arm.cross toolchain is referencing internal classes in CDT's managedbuild which aren't accessible. This is an incompatibility between your arm toolchain and CDT. You should file a bug with them on this error, first trying a newer version.