[GitHub] [pulsar] eolivelli commented on a change in pull request #10922: Explicitly set the Pulsar function classloader

[GitBox <gi...@apache.org>]

eolivelli commented on a change in pull request #10922:
URL: https://github.com/apache/pulsar/pull/10922#discussion_r651132270



##########
File path: pulsar-client-api/src/main/java/org/apache/pulsar/client/internal/ReflectionUtils.java
##########
@@ -21,15 +21,30 @@
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import lombok.experimental.UtilityClass;
 
 @UtilityClass
-class ReflectionUtils {
-    interface SupplierWithException<T> {
+public class ReflectionUtils {
+
+    private static final Map<String, Class<?>> loadedClasses = new ConcurrentHashMap<>();
+
+    private static volatile ClassLoader classLoader = ReflectionUtils.class.getClassLoader();
+
+    /**
+     * Change the classloader to be used for loading Pulsar client implementation classes
+     * @param newClassLoader
+     */
+    public static void setClassLoader(ClassLoader newClassLoader) {
+        classLoader = newClassLoader;

Review comment:
       This may sound like a security hole unfortunately. 
   In an environment where you are simply running the Pulsar Client and there are multiple users one malicious user may try to override this classloader and inject bad stuff.
   
   This mechanism makes sense only  in Pulsar Functions runtime.
   We should add something (a system property?) To enable this method
   or at least allow this method to be called only once.




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