append put action

Author: hailshao

log4j-core/src/main/java/org/apache/logging/log4j/core/impl/ThrowableProxyHelper.java

@@ -208,6 +208,7 @@ private static Class<?> loadClass(final ClassLoader lastLoader, final String cla
             try {
                 clazz = lastLoader.loadClass(className);
                 if (clazz != null) {
+                    className2ClassMap.put(className, clazz);
                     return clazz;
                 }
             } catch (final Throwable ignore) {
@@ -217,10 +218,11 @@ private static Class<?> loadClass(final ClassLoader lastLoader, final String cla
         try {
             clazz = LoaderUtil.loadClass(className);
         } catch (final ClassNotFoundException | NoClassDefFoundError e) {
-            return loadClass(className);
+            clazz = loadClass(className);
         } catch (final SecurityException e) {
             return null;
         }
+        className2ClassMap.put(className, clazz);
         return clazz;
     }