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fix classloader dead lock in jdk7+ (#2016)

This commit is contained in:
caoyixiong 2018-12-07 15:22:24 +08:00 committed by 吴晟 Wu Sheng
parent 40eb651238
commit f8d384ee76
1 changed files with 27 additions and 0 deletions
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27
apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/plugin/loader/AgentClassLoader.java
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@ -23,6 +23,7 @@ import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Enumeration;
@ -45,6 +46,11 @@ import org.apache.skywalking.apm.agent.core.plugin.PluginBootstrap;
* @author wusheng
*/
public class AgentClassLoader extends ClassLoader {
static {
tryRegisterAsParallelCapable();
}
private static final ILog logger = LogManager.getLogger(AgentClassLoader.class);
/**
* The default class loader for the agent.
@ -55,6 +61,27 @@ public class AgentClassLoader extends ClassLoader {
private List<Jar> allJars;
private ReentrantLock jarScanLock = new ReentrantLock();
/**
* Functional Description: solve the classloader dead lock when jvm start
* only support JDK7+, since ParallelCapable appears in JDK7+
*/
private static void tryRegisterAsParallelCapable() {
Method[] methods = ClassLoader.class.getDeclaredMethods();
for (int i = 0; i < methods.length; i++) {
Method method = methods[i];
String methodName = method.getName();
if ("registerAsParallelCapable".equalsIgnoreCase(methodName)) {
try {
method.setAccessible(true);
method.invoke(null);
} catch (Exception e) {
logger.warn(e, "can not invoke ClassLoader.registerAsParallelCapable()");
}
return;
}
}
}
public static AgentClassLoader getDefault() {
return DEFAULT_LOADER;
}