From e4516e38226b28d321135311f5fe23723ea63bc6 Mon Sep 17 00:00:00 2001
From: Jason Song <nobodyiam@gmail.com>
Date: Sat, 1 Jan 2022 12:49:43 +0800
Subject: [PATCH] Catch LinkageError for ClassLoaderUtil.isClassPresent in case
 class is present but is failed to load

---
 CHANGES.md                                    |  1 +
 .../apollo/core/utils/ClassLoaderUtil.java    |  6 ++-
 .../core/utils/ClassLoaderUtilTest.java       | 53 +++++++++++++++++++
 3 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 apollo-core/src/test/java/com/ctrip/framework/apollo/core/utils/ClassLoaderUtilTest.java

diff --git a/CHANGES.md b/CHANGES.md
index b75a02eadea..4411409bf67 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -8,6 +8,7 @@ Apollo 1.9.2
 * [Fix the issue that property placeholder doesn't work for dubbo reference beans](https://github.com/apolloconfig/apollo/pull/4161)
 * [Update xstream version to 1.4.18](https://github.com/apolloconfig/apollo/pull/4177)
 * [Fix the NPE occurred when using EnableApolloConfig with Spring 3.1.1](https://github.com/apolloconfig/apollo/pull/4179)
+* [Catch LinkageError for ClassLoaderUtil.isClassPresent in case class is present but is failed to load](https://github.com/apolloconfig/apollo/pull/4187)
 
 ------------------
 All issues and pull requests are [here](https://github.com/apolloconfig/apollo/milestone/10?closed=1)
diff --git a/apollo-core/src/main/java/com/ctrip/framework/apollo/core/utils/ClassLoaderUtil.java b/apollo-core/src/main/java/com/ctrip/framework/apollo/core/utils/ClassLoaderUtil.java
index 9d82d3d1efc..5ced2bd2c33 100644
--- a/apollo-core/src/main/java/com/ctrip/framework/apollo/core/utils/ClassLoaderUtil.java
+++ b/apollo-core/src/main/java/com/ctrip/framework/apollo/core/utils/ClassLoaderUtil.java
@@ -61,7 +61,6 @@ public static ClassLoader getLoader() {
     return loader;
   }
 
-
   public static String getClassPath() {
     return classPath;
   }
@@ -71,6 +70,11 @@ public static boolean isClassPresent(String className) {
       Class.forName(className);
       return true;
     } catch (ClassNotFoundException ex) {
+      // ignore expected exception
+      return false;
+    } catch (LinkageError ex) {
+      // unexpected error, need to let the user know the actual error
+      logger.error("Failed to load class: {}", className, ex);
       return false;
     }
   }
diff --git a/apollo-core/src/test/java/com/ctrip/framework/apollo/core/utils/ClassLoaderUtilTest.java b/apollo-core/src/test/java/com/ctrip/framework/apollo/core/utils/ClassLoaderUtilTest.java
new file mode 100644
index 00000000000..6c11051d1a2
--- /dev/null
+++ b/apollo-core/src/test/java/com/ctrip/framework/apollo/core/utils/ClassLoaderUtilTest.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2021 Apollo Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+package com.ctrip.framework.apollo.core.utils;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+public class ClassLoaderUtilTest {
+  private static boolean shouldFailInInitialization = false;
+  @Test
+  public void testGetClassLoader() {
+    assertNotNull(ClassLoaderUtil.getLoader());
+  }
+
+  @Test
+  public void testIsClassPresent() {
+    assertTrue(ClassLoaderUtil.isClassPresent("java.lang.String"));
+  }
+
+  @Test
+  public void testIsClassPresentWithClassNotFound() {
+    assertFalse(ClassLoaderUtil.isClassPresent("java.lang.StringNotFound"));
+  }
+
+  @Test
+  public void testIsClassPresentWithLinkageError() {
+    shouldFailInInitialization = true;
+    assertFalse(ClassLoaderUtil.isClassPresent(ClassWithInitializationError.class.getName()));
+  }
+
+  public static class ClassWithInitializationError {
+    static {
+      if (ClassLoaderUtilTest.shouldFailInInitialization) {
+        throw new RuntimeException("Some initialization exception");
+      }
+    }
+  }
+}
\ No newline at end of file