From da9435182a8fccec743406e089325655138d9de8 Mon Sep 17 00:00:00 2001
From: Akira Ajisaka <aajisaka@apache.org>
Date: Mon, 25 Nov 2019 14:36:27 +0900
Subject: [PATCH] HADOOP-16717. Remove GenericsUtil isLog4jLogger dependency on
 Log4jLoggerAdapter. Contributed by Xieming Li.

---
 .../main/java/org/apache/hadoop/util/GenericsUtil.java    | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/GenericsUtil.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/GenericsUtil.java
index a53096a957..0aba34845a 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/GenericsUtil.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/GenericsUtil.java
@@ -25,7 +25,6 @@
 import org.apache.hadoop.classification.InterfaceStability;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import org.slf4j.impl.Log4jLoggerAdapter;
 
 /**
  * Contains utility methods for dealing with Java Generics. 
@@ -85,6 +84,11 @@ public static boolean isLog4jLogger(Class<?> clazz) {
       return false;
     }
     Logger log = LoggerFactory.getLogger(clazz);
-    return log instanceof Log4jLoggerAdapter;
+    try {
+      Class log4jClass = Class.forName("org.slf4j.impl.Log4jLoggerAdapter");
+      return log4jClass.isInstance(log);
+    } catch (ClassNotFoundException e) {
+      return false;
+    }
   }
 }