org.glowroot.instrumentation.engine.init.MainEntryPointUtil Maven / Gradle / Ivy
/*
* Copyright 2019 the original author or 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 org.glowroot.instrumentation.engine.init;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.lang.instrument.Instrumentation;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.glowroot.instrumentation.test.harness.shaded.org.slf4j.Logger;
import org.glowroot.instrumentation.test.harness.shaded.org.slf4j.LoggerFactory;
import org.glowroot.instrumentation.engine.init.PreCheckLoadedClasses.PreCheckClassFileTransformer;
import org.glowroot.instrumentation.engine.util.JavaVersion;
public class MainEntryPointUtil {
private MainEntryPointUtil() {}
public static Logger initLogging(String name, @Nullable Instrumentation instrumentation) {
if (JavaVersion.isJava6() && "IBM J9 VM".equals(System.getProperty("java.vm.name"))
&& instrumentation != null) {
instrumentation.addTransformer(new IbmJ9Java6HackClassFileTransformer2());
// don't remove transformer in case the class is retransformed later
}
ClassLoader priorLoader = Thread.currentThread().getContextClassLoader();
// setting the context class loader to only load from bootstrap class loader (by specifying
// null parent class loader), otherwise logback will pick up and use a SAX parser on the
// system classpath because SAXParserFactory.newInstance() checks the thread context class
// loader for resource named META-INF/services/javax.xml.parsers.SAXParserFactory
Thread.currentThread().setContextClassLoader(new ClassLoader(null) {
// overriding getResourceAsStream() is needed for JDK 6 since it still manages to
// fallback and find the resource on the system class path otherwise
@Override
public @Nullable InputStream getResourceAsStream(String name) {
if (name.equals("META-INF/services/javax.xml.parsers.SAXParserFactory")) {
return new ByteArrayInputStream(new byte[0]);
}
return null;
}
});
try {
Logger logger = LoggerFactory.getLogger(name);
PreCheckClassFileTransformer.initLogger();
return logger;
} finally {
Thread.currentThread().setContextClassLoader(priorLoader);
}
}
}