theonedev/onedev · error · org.apache.wicket.WicketRuntimeException

org.apache.wicket.WicketRuntimeException

Error message

org.apache.wicket.WicketRuntimeException

What it means

AbstractClassResolver.getResources() wraps any exception from ClassLoader.getResources(name) (I/O or lookup failure while scanning classpath resources) in a WicketRuntimeException. It signals the classloader failed to enumerate resources for a given name, not that resources were absent (empty results are legal).

Source

Thrown at server-core/src/main/java/org/apache/wicket/application/AbstractClassResolver.java:147

		Set<URL> resultSet = new TreeSet<>(new UrlExternalFormComparator());

		try
		{
			// Try the classloader for the wicket jar/bundle
			Enumeration<URL> resources = Application.class.getClassLoader().getResources(name);
			loadResources(resources, resultSet);

			// Try the classloader for the user's application jar/bundle
			resources = Application.get().getClass().getClassLoader().getResources(name);
			loadResources(resources, resultSet);

			// Try the context class loader
			resources = getClassLoader().getResources(name);
			loadResources(resources, resultSet);
		}
		catch (Exception e)
		{
			throw new WicketRuntimeException(e);
		}

		return resultSet.iterator();
	}

	/**
	 * 
	 * @param resources
	 * @param loadedResources
	 */
	private void loadResources(Enumeration<URL> resources, Set<URL> loadedResources)
	{
		if (resources != null)
		{
			while (resources.hasMoreElements())
			{
				final URL url = resources.nextElement();
				loadedResources.add(url);

View on GitHub (pinned to d44925c47c)

Solutions

1. Inspect the cause for the underlying IOException/classloader problem
2. Clean and redeploy the application — stale or corrupted jars in WEB-INF/lib are common culprits
3. Verify the thread context classloader is set correctly (Thread.currentThread().setContextClassLoader) in embedded/custom environments
4. Restart the application server to clear closed classloaders after hot redeploy

Example fix

// before
Thread.currentThread().setContextClassLoader(oldLoader); // wrong/closed loader
// after
Thread.currentThread().setContextClassLoader(getClass().getClassLoader());

try {
    resolver.getResources(name);
} catch (WicketRuntimeException e) {
    log.error("Classpath resource scan failed", e.getCause());
    // trigger redeploy/restart path
}

When it happens

Trigger: ClassLoader.getResources throws — e.g. the context classloader is broken/closed, an app-server redeploy closed the old loader, or an I/O error reading a jar/directory on the classpath during scanning.

Common situations: Hot redeploys in Tomcat/Jetty leaving stale classloaders; corrupted jars in WEB-INF/lib; OSGi or exotic classloader environments where getResources misbehaves; classpath scanning of initializer patterns (META-INF/*).

Related errors

• Page classes should extend from BasePage.
• Base resource mapper should be used
• Invalid date range, expecting "yyyy-MM-dd to yyyy-MM-dd"
• Path '${mountPath}' should be mounted to a svg sprite resour
• Unable to find svg sprite resource mounted at: ${mountPath}

AI-assisted analysis of theonedev/onedev@d44925c47c (2026-09-06). Data as JSON: /api/errors/e3e311580b95533f. Report an issue: GitHub.