pinpoint-apm/pinpoint · warning

Failed to load plugin resource as stream {} with classLoader

Error message

Failed to load plugin resource as stream {} with classLoader {}

What it means

PlainClassLoaderHandler.getResourceAsStream fetches the bytecode stream of a plugin class resource from the target classloader (with a plugin-jar fallback). If the lookup throws any Exception, the handler logs this warn and returns null instead of propagating. A null return means the resource could not be loaded, not necessarily that it does not exist.

Source

Thrown at agent-module/profiler/src/main/java/com/navercorp/pinpoint/profiler/instrument/classloading/PlainClassLoaderHandler.java:105

        try {
            final String name = JavaAssistUtils.jvmNameToJavaName(internalName);
            if (!isPluginPackage(name, targetClassLoader)) {
                return targetClassLoader.getResourceAsStream(internalName);
            }

            getClassLoaderAttachment(targetClassLoader, internalName);
            final InputStream inputStream = getPluginInputStream(internalName);
            if (inputStream != null) {
                return inputStream;
            }

            if (logger.isInfoEnabled()) {
                logger.info("can not find resource : {} {} ", internalName, pluginConfig.getPluginJarURLExternalForm());
            }
            // fallback
            return targetClassLoader.getResourceAsStream(internalName);
        } catch (Exception e) {
            logger.warn("Failed to load plugin resource as stream {} with classLoader {}", internalName, targetClassLoader, e);
            return null;
        }
    }

    private boolean isPluginPackage(String className, ClassLoader classLoader) {
        return pluginConfig.getPluginPackageFilter().accept(className, classLoader);
    }

    private boolean meetsRequirement(String className, ClassLoader classLoader) {
        return pluginConfig.getPluginPackageRequirementFilter().accept(className, classLoader);
    }

    private Class<?> injectClass0(ClassLoader classLoader, String className) throws IllegalArgumentException {
        if (isDebug) {
            logger.debug("Inject class className:{} cl:{}", className, classLoader);
        }
        final String pluginJarPath = pluginConfig.getPluginJarURLExternalForm();
        final ClassLoaderAttachment attachment = getClassLoaderAttachment(classLoader, pluginJarPath);

View on GitHub (pinned to 744c3d3075)

Solutions

1. Read the attached exception stack trace for the underlying cause.
2. Confirm internalName format (e.g. com/example/Foo.class) and that the resource is packaged in the plugin jar.
3. Handle the null return at the call site before using the stream.
4. If the 'can not find resource' info log precedes it, verify the plugin jar URL is correct and accessible.

Example fix

// before
byte[] bytes = IOUtils.toByteArray(injector.getResourceAsStream(cl, internalName));
// after
InputStream in = injector.getResourceAsStream(cl, internalName);
byte[] bytes = in == null ? null : IOUtils.toByteArray(in);

if (internalName == null || !internalName.endsWith(".class")) { throw new IllegalArgumentException("bad internalName: " + internalName); }

InputStream in = handler.getResourceAsStream(cl, internalName);
if (in == null) { return fallbackStream(internalName); } // e.g. targetClassLoader.getResourceAsStream

When it happens

Trigger: Any exception thrown while resolving the plugin config or calling targetClassLoader.getResourceAsStream(internalName) — I/O errors, security exceptions, malformed internalName, or classloader state problems.

Common situations: Resource name format wrong (must be internal name + ".class"); classloader closed (webapp redeploy); plugin jar unreadable; security manager restrictions.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• Failed to load plugin resource as stream {} with classLoader
• Failed to load plugin resource as stream {} with classLoader
• IOException parsing
• Error opening stream :
• not found Caused by:

AI-assisted analysis of pinpoint-apm/pinpoint@744c3d3075 (2026-09-07). Data as JSON: /api/errors/05e28d614b9df7bc. Report an issue: GitHub.