Fix: Try loading classes using the thread context class loader

LTTngAgent should load classes using the current thread context's
class loader and then try using the system class loader if a
ClassNotFoundException is thrown.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/liblttng-ust-java-agent/java/org/lttng/ust/agent/LTTngAgent.java b/liblttng-ust-java-agent/java/org/lttng/ust/agent/LTTngAgent.java
index 293ac848fba937fa79d40113f871344f8bec7595..47b45197ad8c1584594b01c69c24d700130972bf 100644 (file)
--- a/liblttng-ust-java-agent/java/org/lttng/ust/agent/LTTngAgent.java
+++ b/liblttng-ust-java-agent/java/org/lttng/ust/agent/LTTngAgent.java
@@ -94,8 +94,7 @@ public class LTTngAgent {
                Class<?> logging;
 
                try {
-                       ClassLoader loader = ClassLoader.getSystemClassLoader();
-                       logging = loader.loadClass("org.apache.log4j.spi.LoggingEvent");
+                       logging = loadClass("org.apache.log4j.spi.LoggingEvent");
                } catch (ClassNotFoundException e) {
                        /* Log4j classes not found, no need to create the relevant objects */
                        return false;
@@ -131,10 +130,26 @@ public class LTTngAgent {
                return true;
        }
 
+       private Class<?> loadClass(String className) throws ClassNotFoundException {
+               ClassLoader loader;
+               Class<?> loadedClass;
+
+               try {
+                       /* Try to load class using the current thread's context class loader */
+                       loader = Thread.currentThread().getContextClassLoader();
+                       loadedClass = loader.loadClass(className);
+               } catch (ClassNotFoundException e) {
+                       /* Loading failed, try using the system class loader */
+                       loader = ClassLoader.getSystemClassLoader();
+                       loadedClass = loader.loadClass(className);
+               }
+
+               return loadedClass;
+       }
+
        private void initAgentJULClasses() {
                try {
-                       ClassLoader loader = ClassLoader.getSystemClassLoader();
-                       Class<?> lttngJUL = loader.loadClass("org.lttng.ust.agent.jul.LTTngJUL");
+                       Class<?> lttngJUL = loadClass("org.lttng.ust.agent.jul.LTTngJUL");
                        this.julUser = (LogFramework)lttngJUL.getDeclaredConstructor(new Class[] {Boolean.class}).newInstance(false);
                        this.julRoot = (LogFramework)lttngJUL.getDeclaredConstructor(new Class[] {Boolean.class}).newInstance(true);
                        this.useJUL = true;
@@ -154,8 +169,7 @@ public class LTTngAgent {
 
        private void initAgentLog4jClasses() {
                try {
-                       ClassLoader loader = ClassLoader.getSystemClassLoader();
-                       Class<?> lttngLog4j = loader.loadClass("org.lttng.ust.agent.log4j.LTTngLog4j");
+                       Class<?> lttngLog4j = loadClass("org.lttng.ust.agent.log4j.LTTngLog4j");
                        this.log4jUser = (LogFramework)lttngLog4j.getDeclaredConstructor(new Class[] {Boolean.class}).newInstance(false);
                        this.log4jRoot = (LogFramework)lttngLog4j.getDeclaredConstructor(new Class[] {Boolean.class}).newInstance(true);
                        this.useLog4j = true;