From ab2e0d0ba2697ba0750ec52fbb3b3a0187734a4b Mon Sep 17 00:00:00 2001
From: Danny Chan <yuzhao.cyz@gmail.com>
Date: Tue, 27 Jul 2021 15:18:05 +0800
Subject: [PATCH] [HUDI-2219] Fix NPE of HoodieConfig (#3342)

---
 .../hudi/common/util/ReflectionUtils.java     | 20 ++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/hudi-common/src/main/java/org/apache/hudi/common/util/ReflectionUtils.java b/hudi-common/src/main/java/org/apache/hudi/common/util/ReflectionUtils.java
index 2895f46db..55db2a704 100644
--- a/hudi-common/src/main/java/org/apache/hudi/common/util/ReflectionUtils.java
+++ b/hudi-common/src/main/java/org/apache/hudi/common/util/ReflectionUtils.java
@@ -45,19 +45,21 @@ public class ReflectionUtils {
 
   private static final Logger LOG = LogManager.getLogger(ReflectionUtils.class);
 
-  private static Map<String, Class<?>> clazzCache = new HashMap<>();
+  private static final Map<String, Class<?>> CLAZZ_CACHE = new HashMap<>();
 
   public static Class<?> getClass(String clazzName) {
-    if (!clazzCache.containsKey(clazzName)) {
-      try {
-        Class<?> clazz = Class.forName(clazzName, true,
-                Thread.currentThread().getContextClassLoader());
-        clazzCache.put(clazzName, clazz);
-      } catch (ClassNotFoundException e) {
-        throw new HoodieException("Unable to load class", e);
+    synchronized (CLAZZ_CACHE) {
+      if (!CLAZZ_CACHE.containsKey(clazzName)) {
+        try {
+          Class<?> clazz = Class.forName(clazzName, true,
+              Thread.currentThread().getContextClassLoader());
+          CLAZZ_CACHE.put(clazzName, clazz);
+        } catch (ClassNotFoundException e) {
+          throw new HoodieException("Unable to load class", e);
+        }
       }
     }
-    return clazzCache.get(clazzName);
+    return CLAZZ_CACHE.get(clazzName);
   }
 
   public static <T> T loadClass(String fqcn) {