From 4cf5d3b3a48dbdcbc186e57ad323e2e7593b917a Mon Sep 17 00:00:00 2001
From: hengyunabc <hengyunabc@gmail.com>
Date: Tue, 31 Dec 2019 15:43:13 +0800
Subject: [PATCH] Avoid append spy jar to BootstrapClassLoader multiple times.
 fix #996

---
 .../com/taobao/arthas/agent/AgentBootstrap.java     | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/agent/src/main/java/com/taobao/arthas/agent/AgentBootstrap.java b/agent/src/main/java/com/taobao/arthas/agent/AgentBootstrap.java
index ea0b22e7..132b607d 100644
--- a/agent/src/main/java/com/taobao/arthas/agent/AgentBootstrap.java
+++ b/agent/src/main/java/com/taobao/arthas/agent/AgentBootstrap.java
@@ -71,7 +71,18 @@ public class AgentBootstrap {
 
     private static ClassLoader getClassLoader(Instrumentation inst, File spyJarFile, File agentJarFile) throws Throwable {
         // 将Spy添加到BootstrapClassLoader
-        inst.appendToBootstrapClassLoaderSearch(new JarFile(spyJarFile));
+        ClassLoader parent = ClassLoader.getSystemClassLoader().getParent();
+        Class<?> spyClass = null;
+        if (parent != null) {
+            try {
+                parent.loadClass("java.arthas.Spy");
+            } catch (Throwable e) {
+                // ignore
+            }
+        }
+        if (spyClass == null) {
+            inst.appendToBootstrapClassLoaderSearch(new JarFile(spyJarFile));
+        }
 
         // 构造自定义的类加载器，尽量减少Arthas对现有工程的侵蚀
         return loadOrDefineClassLoader(agentJarFile);