Custom distro got InaccessibleObjectException

[fangjian0423]

Hi team,

I have a custom distro, and will use URLClassLoader to load some 3rd libraries dynamically on the bootstrap phase.

Given URLClassLoader#addURL is a protected method, I should use reflection to get this method to invoke.

The code snippet like:

URL url = file.toURI().toURL();
URLClassLoader.class.getDeclaredMethod("addURL", URL.class);
ADD_URL.setAccessible(true); // got error
addURL().invoke(classLoader, url);

I got below error when I use reflection:

Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make protected void java.net.URLClassLoader.addURL(java.net.URL) accessible: module java.base does not "opens java.net" to unnamed module @32f1fafe

The workaround is adding a extra startup option --add-opens=java.base/java.net=ALL-UNNAMED.

I want to ask is there any ways to resolve it in otel-agent self programmatically?

Thank you!

[laurit]

See

opentelemetry-java-instrumentation/muzzle/src/main/java/io/opentelemetry/javaagent/tooling/muzzle/AgentCachingPoolStrategy.java

Lines 90 to 120 in faff2d9

	private static Method getFindLoadedClassMethod() {
	// instrumentation is null when this code is called from muzzle
	Instrumentation instrumentation = InstrumentationHolder.getInstrumentation();
	if (instrumentation == null) {
	return null;
	}
	if (JavaModule.isSupported()) {
	// ensure that we have access to ClassLoader.findLoadedClass
	// if modular runtime is used export java.lang package from java.base module to the
	// module of this class
	JavaModule currentModule = JavaModule.ofType(AgentCachingPoolStrategy.class);
	JavaModule javaBase = JavaModule.ofType(ClassLoader.class);
	if (javaBase != null && javaBase.isNamed() && currentModule != null) {
	ClassInjector.UsingInstrumentation.redefineModule(
	instrumentation,
	javaBase,
	Collections.emptySet(),
	Collections.emptyMap(),
	Collections.singletonMap("java.lang", Collections.singleton(currentModule)),
	Collections.emptySet(),
	Collections.emptyMap());
	}
	}
	try {
	Method method = ClassLoader.class.getDeclaredMethod("findLoadedClass", String.class);
	method.setAccessible(true);
	return method;
	} catch (NoSuchMethodException exception) {
	throw new IllegalStateException(exception);
	}
	}