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apache / tomcat / HEAD / . / java / org / apache / catalina / loader / WebappClassLoaderBase.java
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.catalina.loader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.lang.ref.Reference;
import java.lang.reflect.Field;
import java.lang.reflect.InaccessibleObjectException;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;
import java.security.CodeSource;
import java.security.Permission;
import java.security.PermissionCollection;
import java.security.ProtectionDomain;
import java.security.cert.Certificate;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.ConcurrentModificationException;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.jar.Attributes;
import java.util.jar.Attributes.Name;
import java.util.jar.Manifest;
import org.apache.catalina.Container;
import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.LifecycleListener;
import org.apache.catalina.LifecycleState;
import org.apache.catalina.WebResource;
import org.apache.catalina.WebResourceRoot;
import org.apache.catalina.webresources.TomcatURLStreamHandlerFactory;
import org.apache.juli.WebappProperties;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.InstrumentableClassLoader;
import org.apache.tomcat.util.ExceptionUtils;
import org.apache.tomcat.util.IntrospectionUtils;
import org.apache.tomcat.util.buf.ToStringUtil;
import org.apache.tomcat.util.collections.ConcurrentLruCache;
import org.apache.tomcat.util.compat.JreCompat;
import org.apache.tomcat.util.res.StringManager;
import org.apache.tomcat.util.threads.ThreadPoolExecutor;
/**
* Specialized web application class loader.
* <p>
* This class loader is a full reimplementation of the <code>URLClassLoader</code> from the JDK. It is designed to be
* fully compatible with a normal <code>URLClassLoader</code>, although its internal behavior may be completely
* different.
* <p>
* <strong>IMPLEMENTATION NOTE</strong> - By default, this class loader follows the delegation model required by the
* specification. The bootstrap class loader will be queried first, then the local repositories, and only then
* delegation to the parent class loader will occur. This allows the web application to override any shared class except
* the classes from J2SE. Special handling is provided from the JAXP XML parser interfaces, the JNDI interfaces, and the
* classes from the servlet API, which are never loaded from the webapp repositories. The <code>delegate</code> property
* allows an application to modify this behavior to move the parent class loader ahead of the local repositories.
* <p>
* <strong>IMPLEMENTATION NOTE</strong> - Due to limitations in Jasper compilation technology, any repository which
* contains classes from the servlet API will be ignored by the class loader.
* <p>
* <strong>IMPLEMENTATION NOTE</strong> - The class loader generates source URLs which include the full JAR URL when a
* class is loaded from a JAR file, which allows setting security permission at the class level, even when a class is
* contained inside a JAR.
* <p>
* <strong>IMPLEMENTATION NOTE</strong> - Local repositories are searched in the order they are added via the initial
* constructor.
* <p>
* <strong>IMPLEMENTATION NOTE</strong> - As of 8.0, this class loader implements {@link InstrumentableClassLoader},
* permitting web application classes to instrument other classes in the same web application. It does not permit
* instrumentation of system or container classes or classes in other web apps.
*
* @author Remy Maucherat
*/
public abstract class WebappClassLoaderBase extends URLClassLoader
implements Lifecycle, InstrumentableClassLoader, WebappProperties {
private static final Log log = LogFactory.getLog(WebappClassLoaderBase.class);
/**
* List of ThreadGroup names to ignore when scanning for web application started threads that need to be shut down.
*/
private static final List<String> JVM_THREAD_GROUP_NAMES = new ArrayList<>();
private static final String JVM_THREAD_GROUP_SYSTEM = "system";
private static final String CLASS_FILE_SUFFIX = ".class";
static {
if (!JreCompat.isGraalAvailable()) {
registerAsParallelCapable();
}
JVM_THREAD_GROUP_NAMES.add(JVM_THREAD_GROUP_SYSTEM);
JVM_THREAD_GROUP_NAMES.add("RMI Runtime");
}
// ------------------------------------------------------- Static Variables
/**
* The string manager for this package.
*/
protected static final StringManager sm = StringManager.getManager(WebappClassLoaderBase.class);
// ----------------------------------------------------------- Constructors
/**
* Construct a new ClassLoader with no defined repositories and no parent ClassLoader.
*/
protected WebappClassLoaderBase() {
super(new URL[0]);
ClassLoader p = getParent();
if (p == null) {
p = getSystemClassLoader();
}
this.parent = p;
ClassLoader j = String.class.getClassLoader();
if (j == null) {
j = getSystemClassLoader();
while (j.getParent() != null) {
j = j.getParent();
}
}
this.javaseClassLoader = j;
}
/**
* Construct a new ClassLoader with no defined repositories and the given parent ClassLoader.
* <p>
* Method is used via reflection - see {@link WebappLoader#createClassLoader()}
*
* @param parent Our parent class loader
*/
protected WebappClassLoaderBase(ClassLoader parent) {
super(new URL[0], parent);
ClassLoader p = getParent();
if (p == null) {
p = getSystemClassLoader();
}
this.parent = p;
ClassLoader j = String.class.getClassLoader();
if (j == null) {
j = getSystemClassLoader();
while (j.getParent() != null) {
j = j.getParent();
}
}
this.javaseClassLoader = j;
}
// ----------------------------------------------------- Instance Variables
/**
* Associated web resources for this webapp.
*/
protected WebResourceRoot resources = null;
/**
* The cache of ResourceEntry for classes and resources we have loaded, keyed by resource path, not binary name.
* Path is used as the key since resources may be requested by binary name (classes) or path (other resources such
* as property files) and the mapping from binary name to path is unambiguous but the reverse mapping is ambiguous.
*/
protected final Map<String,ResourceEntry> resourceEntries = new ConcurrentHashMap<>();
/**
* Should this class loader delegate to the parent class loader <strong>before</strong> searching its own
* repositories (i.e. the usual Java2 delegation model)? If set to <code>false</code>, this class loader will search
* its own repositories first, and delegate to the parent only if the class or resource is not found locally. Note
* that the default, <code>false</code>, is the behavior called for by the servlet specification.
*/
protected boolean delegate = false;
private final Map<String,Long> jarModificationTimes = new HashMap<>();
/**
* A list of read File Permission's required if this loader is for a web application context.
*/
protected final ArrayList<Permission> permissionList = new ArrayList<>();
/**
* The PermissionCollection for each CodeSource for a web application context.
*/
protected final HashMap<String,PermissionCollection> loaderPC = new HashMap<>();
/**
* The parent class loader.
*/
protected final ClassLoader parent;
/**
* The bootstrap class loader used to load the JavaSE classes. In some implementations this class loader is always
* <code>null</code> and in those cases {@link ClassLoader#getParent()} will be called recursively on the system
* class loader and the last non-null result used.
*/
private ClassLoader javaseClassLoader;
/**
* Enables the RMI Target memory leak detection to be controlled. This is necessary since the detection can only
* work if some of the modularity checks are disabled.
*/
private boolean clearReferencesRmiTargets = true;
/**
* Should Tomcat attempt to terminate threads that have been started by the web application? Stopping threads is
* performed via the deprecated (for good reason) <code>Thread.stop()</code> method and is likely to result in
* instability. As such, enabling this should be viewed as an option of last resort in a development environment and
* is not recommended in a production environment. If not specified, the default value of <code>false</code> will be
* used.
*/
private boolean clearReferencesStopThreads = false;
/**
* Should Tomcat attempt to terminate any {@link java.util.TimerThread}s that have been started by the web
* application? If not specified, the default value of <code>false</code> will be used.
*/
private boolean clearReferencesStopTimerThreads = false;
/**
* Should Tomcat call {@link org.apache.juli.logging.LogFactory#release(ClassLoader)} when the class loader is
* stopped? If not specified, the default value of <code>true</code> is used. Changing the default setting is likely
* to lead to memory leaks and other issues.
*/
private boolean clearReferencesLogFactoryRelease = true;
/**
* If an HttpClient keep-alive timer thread has been started by this web application and is still running, should
* Tomcat change the context class loader from the current {@link ClassLoader} to {@link ClassLoader#getParent()} to
* prevent a memory leak? Note that the keep-alive timer thread will stop on its own once the keep-alives all expire
* however, on a busy system that might not happen for some time.
*/
private boolean clearReferencesHttpClientKeepAliveThread = true;
/**
* Should Tomcat attempt to clear references to classes loaded by this class loader from ThreadLocals?
*/
private boolean clearReferencesThreadLocals = true;
/**
* Should Tomcat skip the memory leak checks when the web application is stopped as part of the process of shutting
* down the JVM?
*/
private boolean skipMemoryLeakChecksOnJvmShutdown = false;
/**
* Holds the class file transformers decorating this class loader. The CopyOnWriteArrayList is thread safe. It is
* expensive on writes, but those should be rare. It is very fast on reads, since synchronization is not actually
* used. Importantly, the ClassLoader will never block iterating over the transformers while loading a class.
*/
private final List<ClassFileTransformer> transformers = new CopyOnWriteArrayList<>();
/**
* Flag that indicates that {@link #addURL(URL)} has been called which creates a requirement to check the super
* class when searching for resources.
*/
private boolean hasExternalRepositories = false;
/**
* Repositories managed by this class rather than the super class.
*/
private final List<URL> localRepositories = new ArrayList<>();
private volatile LifecycleState state = LifecycleState.NEW;
/*
* Class resources are not cached since they are loaded on first use and the resource is then no longer required. It
* does help, however, to cache classes that are not found as in some scenarios the same class will be searched for
* many times and the greater the number of JARs/classes, the longer that lookup will take.
*/
private final ConcurrentLruCache<String> notFoundClassResources = new ConcurrentLruCache<>(1000);
// ------------------------------------------------------------- Properties
public void setNotFoundClassResourceCacheSize(int notFoundClassResourceCacheSize) {
notFoundClassResources.setLimit(notFoundClassResourceCacheSize);
}
public int getNotFoundClassResourceCacheSize() {
return notFoundClassResources.getLimit();
}
/**
* Set associated resources.
*
* @param resources the resources from which the classloader will load the classes
*/
public void setResources(WebResourceRoot resources) {
this.resources = resources;
}
/**
* @return the context name for this class loader.
*/
public String getContextName() {
if (resources == null) {
return "Unknown";
} else {
return resources.getContext().getBaseName();
}
}
/**
* Return the "delegate first" flag for this class loader.
*
* @return <code>true</code> if the class lookup will delegate to the parent first. The default in Tomcat is
* <code>false</code>.
*/
public boolean getDelegate() {
return this.delegate;
}
/**
* Set the "delegate first" flag for this class loader. If this flag is true, this class loader delegates to the
* parent class loader <strong>before</strong> searching its own repositories, as in an ordinary (non-servlet) chain
* of Java class loaders. If set to <code>false</code> (the default), this class loader will search its own
* repositories first, and delegate to the parent only if the class or resource is not found locally, as per the
* servlet specification.
*
* @param delegate The new "delegate first" flag
*/
public void setDelegate(boolean delegate) {
this.delegate = delegate;
}
public boolean getClearReferencesRmiTargets() {
return this.clearReferencesRmiTargets;
}
public void setClearReferencesRmiTargets(boolean clearReferencesRmiTargets) {
this.clearReferencesRmiTargets = clearReferencesRmiTargets;
}
/**
* @return the clearReferencesStopThreads flag for this Context.
*/
public boolean getClearReferencesStopThreads() {
return this.clearReferencesStopThreads;
}
/**
* Set the clearReferencesStopThreads feature for this Context.
*
* @param clearReferencesStopThreads The new flag value
*/
public void setClearReferencesStopThreads(boolean clearReferencesStopThreads) {
this.clearReferencesStopThreads = clearReferencesStopThreads;
}
/**
* @return the clearReferencesStopTimerThreads flag for this Context.
*/
public boolean getClearReferencesStopTimerThreads() {
return this.clearReferencesStopTimerThreads;
}
/**
* Set the clearReferencesStopTimerThreads feature for this Context.
*
* @param clearReferencesStopTimerThreads The new flag value
*/
public void setClearReferencesStopTimerThreads(boolean clearReferencesStopTimerThreads) {
this.clearReferencesStopTimerThreads = clearReferencesStopTimerThreads;
}
/**
* @return the clearReferencesLogFactoryRelease flag for this Context.
*/
public boolean getClearReferencesLogFactoryRelease() {
return this.clearReferencesLogFactoryRelease;
}
/**
* Set the clearReferencesLogFactoryRelease feature for this Context.
*
* @param clearReferencesLogFactoryRelease The new flag value
*/
public void setClearReferencesLogFactoryRelease(boolean clearReferencesLogFactoryRelease) {
this.clearReferencesLogFactoryRelease = clearReferencesLogFactoryRelease;
}
/**
* @return the clearReferencesHttpClientKeepAliveThread flag for this Context.
*/
public boolean getClearReferencesHttpClientKeepAliveThread() {
return this.clearReferencesHttpClientKeepAliveThread;
}
/**
* Set the clearReferencesHttpClientKeepAliveThread feature for this Context.
*
* @param clearReferencesHttpClientKeepAliveThread The new flag value
*/
public void setClearReferencesHttpClientKeepAliveThread(boolean clearReferencesHttpClientKeepAliveThread) {
this.clearReferencesHttpClientKeepAliveThread = clearReferencesHttpClientKeepAliveThread;
}
public boolean getClearReferencesThreadLocals() {
return clearReferencesThreadLocals;
}
public void setClearReferencesThreadLocals(boolean clearReferencesThreadLocals) {
this.clearReferencesThreadLocals = clearReferencesThreadLocals;
}
public boolean getSkipMemoryLeakChecksOnJvmShutdown() {
return skipMemoryLeakChecksOnJvmShutdown;
}
public void setSkipMemoryLeakChecksOnJvmShutdown(boolean skipMemoryLeakChecksOnJvmShutdown) {
this.skipMemoryLeakChecksOnJvmShutdown = skipMemoryLeakChecksOnJvmShutdown;
}
// ------------------------------------------------------- Reloader Methods
@Override
public void addTransformer(ClassFileTransformer transformer) {
if (transformer == null) {
throw new IllegalArgumentException(
sm.getString("webappClassLoader.addTransformer.illegalArgument", getContextName()));
}
if (this.transformers.contains(transformer)) {
// if the same instance of this transformer was already added, bail out
log.warn(sm.getString("webappClassLoader.addTransformer.duplicate", transformer, getContextName()));
return;
}
this.transformers.add(transformer);
log.info(sm.getString("webappClassLoader.addTransformer", transformer, getContextName()));
}
@Override
public void removeTransformer(ClassFileTransformer transformer) {
if (transformer == null) {
return;
}
if (this.transformers.remove(transformer)) {
log.info(sm.getString("webappClassLoader.removeTransformer", transformer, getContextName()));
}
}
protected void copyStateWithoutTransformers(WebappClassLoaderBase base) {
base.resources = this.resources;
base.delegate = this.delegate;
base.state = LifecycleState.NEW;
base.clearReferencesStopThreads = this.clearReferencesStopThreads;
base.clearReferencesStopTimerThreads = this.clearReferencesStopTimerThreads;
base.clearReferencesLogFactoryRelease = this.clearReferencesLogFactoryRelease;
base.clearReferencesHttpClientKeepAliveThread = this.clearReferencesHttpClientKeepAliveThread;
base.jarModificationTimes.putAll(this.jarModificationTimes);
base.permissionList.addAll(this.permissionList);
base.loaderPC.putAll(this.loaderPC);
}
/**
* Have one or more classes or resources been modified so that a reload is appropriate?
*
* @return <code>true</code> if there's been a modification
*/
public boolean modified() {
if (log.isTraceEnabled()) {
log.trace("modified()");
}
for (Entry<String,ResourceEntry> entry : resourceEntries.entrySet()) {
long cachedLastModified = entry.getValue().lastModified;
long lastModified = resources.getClassLoaderResource(entry.getKey()).getLastModified();
if (lastModified != cachedLastModified) {
if (log.isDebugEnabled()) {
log.debug(sm.getString("webappClassLoader.resourceModified", entry.getKey(),
new Date(cachedLastModified), new Date(lastModified)));
}
return true;
}
}
// Check if JARs have been added or removed
WebResource[] jars = resources.listResources("/WEB-INF/lib");
// Filter out non-JAR resources
int jarCount = 0;
for (WebResource jar : jars) {
if (jar.getName().endsWith(".jar") && jar.isFile() && jar.canRead()) {
jarCount++;
Long recordedLastModified = jarModificationTimes.get(jar.getName());
if (recordedLastModified == null) {
// Jar has been added
log.info(sm.getString("webappClassLoader.jarsAdded", resources.getContext().getName()));
return true;
}
if (recordedLastModified.longValue() != jar.getLastModified()) {
// Jar has been changed
log.info(sm.getString("webappClassLoader.jarsModified", resources.getContext().getName()));
return true;
}
}
}
if (jarCount < jarModificationTimes.size()) {
log.info(sm.getString("webappClassLoader.jarsRemoved", resources.getContext().getName()));
return true;
}
// No classes have been modified
return false;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder(this.getClass().getSimpleName());
sb.append("\r\n context: ");
sb.append(getContextName());
sb.append("\r\n delegate: ");
sb.append(delegate);
sb.append("\r\n");
if (this.parent != null) {
sb.append("----------> Parent Classloader:\r\n");
sb.append(this.parent.toString());
sb.append("\r\n");
}
if (!this.transformers.isEmpty()) {
sb.append("----------> Class file transformers:\r\n");
for (ClassFileTransformer transformer : this.transformers) {
sb.append(transformer).append("\r\n");
}
}
return sb.toString();
}
// ---------------------------------------------------- ClassLoader Methods
// Note: exposed for use by tests
protected final Class<?> doDefineClass(String name, byte[] b, int off, int len, ProtectionDomain protectionDomain) {
return super.defineClass(name, b, off, len, protectionDomain);
}
/**
* Find the specified class in our local repositories, if possible. If not found, throw
* <code>ClassNotFoundException</code>.
*
* @param name The binary name of the class to be loaded
*
* @exception ClassNotFoundException if the class was not found
*/
@Override
public Class<?> findClass(String name) throws ClassNotFoundException {
if (log.isTraceEnabled()) {
log.trace(" findClass(" + name + ")");
}
checkStateForClassLoading(name);
if (name == null) {
throw new ClassNotFoundException("null");
}
String path = binaryNameToPath(name, true);
// Ask our superclass to locate this class, if possible
// (throws ClassNotFoundException if it is not found)
Class<?> clazz = null;
try {
if (log.isTraceEnabled()) {
log.trace(" findClassInternal(" + name + ")");
}
if (!notFoundClassResources.contains(path)) {
try {
clazz = findClassInternal(name, path);
} catch (RuntimeException e) {
if (log.isTraceEnabled()) {
log.trace(" -->RuntimeException Rethrown", e);
}
throw e;
}
if (clazz == null && hasExternalRepositories) {
try {
clazz = super.findClass(name);
} catch (RuntimeException e) {
if (log.isTraceEnabled()) {
log.trace(" -->RuntimeException Rethrown", e);
}
throw e;
}
}
}
} catch (ClassNotFoundException e) {
if (log.isTraceEnabled()) {
log.trace(" --> Passing on ClassNotFoundException");
}
notFoundClassResources.add(path);
throw e;
}
if (clazz == null) {
if (log.isTraceEnabled()) {
log.trace(" --> Returning ClassNotFoundException");
}
notFoundClassResources.add(path);
throw new ClassNotFoundException(name);
}
// Return the class we have located
if (log.isTraceEnabled()) {
log.trace(" Returning class " + clazz);
}
if (log.isTraceEnabled()) {
ClassLoader cl = clazz.getClassLoader();
log.trace(" Loaded by " + cl.toString());
}
return clazz;
}
/**
* Find the specified resource in our local repository, and return a <code>URL</code> referring to it, or
* <code>null</code> if this resource cannot be found.
*
* @param name Name of the resource to be found
*/
@Override
public URL findResource(final String name) {
if (log.isTraceEnabled()) {
log.trace(" findResource(" + name + ")");
}
checkStateForResourceLoading(name);
URL url = null;
if (name == null || name.startsWith("/")) {
return null;
}
String path = nameToPath(name);
if (!notFoundClassResources.contains(path)) {
WebResource resource = resources.getClassLoaderResource(path);
if (resource.exists()) {
url = resource.getURL();
trackLastModified(path, resource);
}
if (url == null && hasExternalRepositories) {
url = super.findResource(name);
}
if (url == null) {
notFoundClassResources.add(path);
}
}
if (log.isTraceEnabled()) {
if (url != null) {
log.trace(" --> Returning '" + url.toString() + "'");
} else {
log.trace(" --> Resource not found, returning null");
}
}
return url;
}
private void trackLastModified(String path, WebResource resource) {
if (resourceEntries.containsKey(path)) {
return;
}
ResourceEntry entry = new ResourceEntry();
entry.lastModified = resource.getLastModified();
synchronized (resourceEntries) {
resourceEntries.putIfAbsent(path, entry);
}
}
@Override
public Enumeration<URL> findResources(String name) throws IOException {
if (log.isTraceEnabled()) {
log.trace(" findResources(" + name + ")");
}
checkStateForResourceLoading(name);
LinkedHashSet<URL> result = new LinkedHashSet<>();
if (name == null || name.startsWith("/")) {
return null;
}
String path = nameToPath(name);
WebResource[] webResources = resources.getClassLoaderResources(path);
for (WebResource webResource : webResources) {
if (webResource.exists()) {
result.add(webResource.getURL());
}
}
// Adding the results of a call to the superclass
if (hasExternalRepositories) {
Enumeration<URL> otherResourcePaths = super.findResources(name);
while (otherResourcePaths.hasMoreElements()) {
result.add(otherResourcePaths.nextElement());
}
}
return Collections.enumeration(result);
}
/**
* Find the resource with the given name. A resource is some data (images, audio, text, etc.) that can be accessed
* by class code in a way that is independent of the location of the code. The name of a resource is a "/"-separated
* path name that identifies the resource. If the resource cannot be found, return <code>null</code>.
* <p>
* This method searches according to the following algorithm, returning as soon as it finds the appropriate URL. If
* the resource cannot be found, returns <code>null</code>.
* <ul>
* <li>If the <code>delegate</code> property is set to <code>true</code>, call the <code>getResource()</code> method
* of the parent class loader, if any.</li>
* <li>Call <code>findResource()</code> to find this resource in our locally defined repositories.</li>
* <li>Call the <code>getResource()</code> method of the parent class loader, if any.</li>
* </ul>
*
* @param name Name of the resource to return a URL for
*/
@Override
public URL getResource(String name) {
if (log.isTraceEnabled()) {
log.trace("getResource(" + name + ")");
}
checkStateForResourceLoading(name);
URL url;
boolean delegateFirst = delegate || filter(name, false);
// (1) Delegate to parent if requested
if (delegateFirst) {
if (log.isTraceEnabled()) {
log.trace(" Delegating to parent classloader " + parent);
}
url = parent.getResource(name);
if (url != null) {
if (log.isTraceEnabled()) {
log.trace(" --> Returning '" + url.toString() + "'");
}
return url;
}
}
// (2) Search local repositories
url = findResource(name);
if (url != null) {
if (log.isTraceEnabled()) {
log.trace(" --> Returning '" + url.toString() + "'");
}
return url;
}
// (3) Delegate to parent unconditionally if not already attempted
if (!delegateFirst) {
url = parent.getResource(name);
if (url != null) {
if (log.isTraceEnabled()) {
log.trace(" --> Returning '" + url.toString() + "'");
}
return url;
}
}
// (4) Resource was not found
if (log.isTraceEnabled()) {
log.trace(" --> Resource not found, returning null");
}
return null;
}
@Override
public Enumeration<URL> getResources(String name) throws IOException {
Enumeration<URL> parentResources = parent.getResources(name);
Enumeration<URL> localResources = findResources(name);
// Need to combine these enumerations. The order in which the
// Enumerations are combined depends on how delegation is configured
boolean delegateFirst = delegate || filter(name, false);
if (delegateFirst) {
return new CombinedEnumeration(parentResources, localResources);
} else {
return new CombinedEnumeration(localResources, parentResources);
}
}
/**
* Find the resource with the given name, and return an input stream that can be used for reading it. The search
* order is as described for <code>getResource()</code>, after checking to see if the resource data has been
* previously cached. If the resource cannot be found, return <code>null</code>.
*
* @param name Name of the resource to return an input stream for
*/
@Override
public InputStream getResourceAsStream(String name) {
if (log.isTraceEnabled()) {
log.trace("getResourceAsStream(" + name + ")");
}
checkStateForResourceLoading(name);
InputStream stream = null;
boolean delegateFirst = delegate || filter(name, false);
// (1) Delegate to parent if requested
if (delegateFirst) {
if (log.isTraceEnabled()) {
log.trace(" Delegating to parent classloader " + parent);
}
stream = parent.getResourceAsStream(name);
if (stream != null) {
if (log.isTraceEnabled()) {
log.trace(" --> Returning stream from parent");
}
return stream;
}
}
// (2) Search local repositories
if (log.isTraceEnabled()) {
log.trace(" Searching local repositories");
}
if (name.startsWith("/")) {
return null;
}
String path = nameToPath(name);
if (!notFoundClassResources.contains(path)) {
WebResource resource = resources.getClassLoaderResource(path);
if (resource.exists()) {
stream = resource.getInputStream();
// Filter out .class resources through the ClassFileTranformer
if (name.endsWith(CLASS_FILE_SUFFIX) && !transformers.isEmpty()) {
// If the resource is a class, decorate it with any attached transformers
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buf = new byte[8192];
int numRead;
try {
while ((numRead = stream.read(buf)) >= 0) {
baos.write(buf, 0, numRead);
}
} catch (IOException ioe) {
log.error(sm.getString("webappClassLoader.transformError", name), ioe);
return null;
} finally {
try {
stream.close();
} catch (IOException ignore) {
// Ignore
}
}
byte[] binaryContent = baos.toByteArray();
String internalName = path.substring(1, path.length() - CLASS_FILE_SUFFIX.length());
for (ClassFileTransformer transformer : this.transformers) {
try {
byte[] transformed = transformer.transform(this, internalName, null, null, binaryContent);
if (transformed != null) {
binaryContent = transformed;
}
} catch (IllegalClassFormatException e) {
log.error(sm.getString("webappClassLoader.transformError", name), e);
return null;
}
}
stream = new ByteArrayInputStream(binaryContent);
}
trackLastModified(path, resource);
}
try {
if (hasExternalRepositories && stream == null) {
URL url = super.findResource(name);
if (url != null) {
stream = url.openStream();
}
}
} catch (IOException ioe) {
// Ignore
}
if (stream != null) {
if (log.isTraceEnabled()) {
log.trace(" --> Returning stream from local");
}
return stream;
}
notFoundClassResources.add(path);
}
// (3) Delegate to parent unconditionally
if (!delegateFirst) {
if (log.isTraceEnabled()) {
log.trace(" Delegating to parent classloader unconditionally " + parent);
}
stream = parent.getResourceAsStream(name);
if (stream != null) {
if (log.isTraceEnabled()) {
log.trace(" --> Returning stream from parent");
}
return stream;
}
}
// (4) Resource was not found
if (log.isTraceEnabled()) {
log.trace(" --> Resource not found, returning null");
}
return null;
}
/**
* Load the class with the specified name. This method searches for classes in the same manner as
* <code>loadClass(String, boolean)</code> with <code>false</code> as the second argument.
*
* @param name The binary name of the class to be loaded
*
* @exception ClassNotFoundException if the class was not found
*/
@Override
public Class<?> loadClass(String name) throws ClassNotFoundException {
return loadClass(name, false);
}
/**
* Load the class with the specified name, searching using the following algorithm until it finds and returns the
* class. If the class cannot be found, returns <code>ClassNotFoundException</code>.
* <ul>
* <li>Call <code>findLoadedClass(String)</code> to check if the class has already been loaded. If it has, the same
* <code>Class</code> object is returned.</li>
* <li>If the <code>delegate</code> property is set to <code>true</code>, call the <code>loadClass()</code> method
* of the parent class loader, if any.</li>
* <li>Call <code>findClass()</code> to find this class in our locally defined repositories.</li>
* <li>Call the <code>loadClass()</code> method of our parent class loader, if any.</li>
* </ul>
* If the class was found using the above steps, and the <code>resolve</code> flag is <code>true</code>, this method
* will then call <code>resolveClass(Class)</code> on the resulting Class object.
*
* @param name The binary name of the class to be loaded
* @param resolve If <code>true</code> then resolve the class
*
* @exception ClassNotFoundException if the class was not found
*/
@Override
public Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
synchronized (JreCompat.isGraalAvailable() ? this : getClassLoadingLock(name)) {
if (log.isTraceEnabled()) {
log.trace("loadClass(" + name + ", " + resolve + ")");
}
Class<?> clazz;
// Log access to stopped class loader
checkStateForClassLoading(name);
// (0) Check our previously loaded local class cache
clazz = findLoadedClass0(name);
if (clazz != null) {
if (log.isTraceEnabled()) {
log.trace(" Returning class from cache");
}
if (resolve) {
resolveClass(clazz);
}
return clazz;
}
// (0.1) Check our previously loaded class cache
clazz = JreCompat.isGraalAvailable() ? null : findLoadedClass(name);
if (clazz != null) {
if (log.isTraceEnabled()) {
log.trace(" Returning class from cache");
}
if (resolve) {
resolveClass(clazz);
}
return clazz;
}
/*
* (0.2) Try loading the class with the bootstrap class loader, to prevent the webapp from overriding Java
* SE classes. This implements SRV.10.7.2
*/
String resourceName = binaryNameToPath(name, false);
ClassLoader javaseLoader = getJavaseClassLoader();
boolean tryLoadingFromJavaseLoader;
try {
/*
* Use getResource as it won't trigger an expensive ClassNotFoundException if the resource is not
* available from the Java SE class loader.
*
* See https://bz.apache.org/bugzilla/show_bug.cgi?id=61424 for details of how this may trigger a
* StackOverflowError.
*
* Given these reported errors, catch Throwable to ensure all edge cases are caught.
*/
URL url = javaseLoader.getResource(resourceName);
tryLoadingFromJavaseLoader = url != null;
} catch (Throwable t) {
// Swallow all exceptions apart from those that must be re-thrown
ExceptionUtils.handleThrowable(t);
// The getResource() trick won't work for this class. We have to
// try loading it directly and accept that we might get a
// ClassNotFoundException.
tryLoadingFromJavaseLoader = true;
}
if (tryLoadingFromJavaseLoader) {
try {
clazz = javaseLoader.loadClass(name);
if (clazz != null) {
if (resolve) {
resolveClass(clazz);
}
return clazz;
}
} catch (ClassNotFoundException e) {
// Ignore
}
}
boolean delegateLoad = delegate || filter(name, true);
// (1) Delegate to our parent if requested
if (delegateLoad) {
if (log.isTraceEnabled()) {
log.trace(" Delegating to parent classloader1 " + parent);
}
try {
clazz = Class.forName(name, false, parent);
if (clazz != null) {
if (log.isTraceEnabled()) {
log.trace(" Loading class from parent");
}
if (resolve) {
resolveClass(clazz);
}
return clazz;
}
} catch (ClassNotFoundException e) {
// Ignore
}
}
// (2) Search local repositories
if (log.isTraceEnabled()) {
log.trace(" Searching local repositories");
}
try {
clazz = findClass(name);
if (clazz != null) {
if (log.isTraceEnabled()) {
log.trace(" Loading class from local repository");
}
if (resolve) {
resolveClass(clazz);
}
return clazz;
}
} catch (ClassNotFoundException e) {
// Ignore
}
// (3) Delegate to parent unconditionally
if (!delegateLoad) {
if (log.isTraceEnabled()) {
log.trace(" Delegating to parent classloader at end: " + parent);
}
try {
clazz = Class.forName(name, false, parent);
if (clazz != null) {
if (log.isTraceEnabled()) {
log.trace(" Loading class from parent");
}
if (resolve) {
resolveClass(clazz);
}
return clazz;
}
} catch (ClassNotFoundException e) {
// Ignore
}
}
}
if (log.isDebugEnabled()) {
log.debug(ToStringUtil.classPathForCNFE(this));
}
throw new ClassNotFoundException(name);
}
protected void checkStateForClassLoading(String className) throws ClassNotFoundException {
// It is not permitted to load new classes once the web application has
// been stopped.
try {
checkStateForResourceLoading(className);
} catch (IllegalStateException ise) {
throw new ClassNotFoundException(ise.getMessage(), ise);
}
}
protected void checkStateForResourceLoading(String resource) throws IllegalStateException {
// It is not permitted to load resources once the web application has
// been stopped.
if (!state.isAvailable()) {
IllegalStateException ise = new IllegalStateException(sm.getString("webappClassLoader.stopped", resource));
log.info(ise.getMessage(), ise);
throw ise;
}
}
/**
* Get the Permissions for a CodeSource. If this instance of WebappClassLoaderBase is for a web application context,
* add read FilePermission for the appropriate resources.
*
* @param codeSource where the code was loaded from
*
* @return PermissionCollection for CodeSource
*/
@Override
protected PermissionCollection getPermissions(CodeSource codeSource) {
return null;
}
/**
* {@inheritDoc}
* <p>
* Note that list of URLs returned by this method may not be complete. The web application class loader accesses
* class loader resources via the {@link WebResourceRoot} which supports the arbitrary mapping of additional files,
* directories and contents of JAR files under WEB-INF/classes. Any such resources will not be included in the URLs
* returned here.
*/
@Override
public URL[] getURLs() {
ArrayList<URL> result = new ArrayList<>();
result.addAll(localRepositories);
result.addAll(Arrays.asList(super.getURLs()));
return result.toArray(new URL[0]);
}
// ------------------------------------------------------ Lifecycle Methods
@Override
public void addLifecycleListener(LifecycleListener listener) {
// NOOP
}
@Override
public LifecycleListener[] findLifecycleListeners() {
return new LifecycleListener[0];
}
@Override
public void removeLifecycleListener(LifecycleListener listener) {
// NOOP
}
@Override
public LifecycleState getState() {
return state;
}
@Override
public String getStateName() {
return getState().toString();
}
@Override
public void init() {
state = LifecycleState.INITIALIZED;
}
@Override
public void start() throws LifecycleException {
state = LifecycleState.STARTING_PREP;
WebResource[] classesResources = resources.getResources("/WEB-INF/classes");
for (WebResource classes : classesResources) {
if (classes.isDirectory() && classes.canRead()) {
localRepositories.add(classes.getURL());
}
}
WebResource[] jars = resources.listResources("/WEB-INF/lib");
for (WebResource jar : jars) {
if (jar.getName().endsWith(".jar") && jar.isFile() && jar.canRead()) {
localRepositories.add(jar.getURL());
jarModificationTimes.put(jar.getName(), Long.valueOf(jar.getLastModified()));
}
}
state = LifecycleState.STARTED;
}
@Override
public void stop() throws LifecycleException {
state = LifecycleState.STOPPING_PREP;
// Clearing references should be done before setting started to
// false, due to possible side effects
clearReferences();
state = LifecycleState.STOPPING;
resourceEntries.clear();
notFoundClassResources.clear();
jarModificationTimes.clear();
resources = null;
permissionList.clear();
loaderPC.clear();
state = LifecycleState.STOPPED;
}
@Override
public void destroy() {
state = LifecycleState.DESTROYING;
try {
super.close();
} catch (IOException ioe) {
log.warn(sm.getString("webappClassLoader.superCloseFail"), ioe);
}
state = LifecycleState.DESTROYED;
}
// ------------------------------------------------------ Protected Methods
protected ClassLoader getJavaseClassLoader() {
return javaseClassLoader;
}
protected void setJavaseClassLoader(ClassLoader classLoader) {
if (classLoader == null) {
throw new IllegalArgumentException(sm.getString("webappClassLoader.javaseClassLoaderNull"));
}
javaseClassLoader = classLoader;
}
/**
* Clear references.
*/
protected void clearReferences() {
// If the JVM is shutting down, skip the memory leak checks
if (skipMemoryLeakChecksOnJvmShutdown && !resources.getContext().getParent().getState().isAvailable()) {
// During reloading / redeployment the parent is expected to be
// available. Parent is not available so this might be a JVM
// shutdown.
try {
Thread dummyHook = new Thread();
Runtime.getRuntime().addShutdownHook(dummyHook);
Runtime.getRuntime().removeShutdownHook(dummyHook);
} catch (IllegalStateException ise) {
return;
}
}
if (!JreCompat.isGraalAvailable()) {
// De-register any remaining JDBC drivers
clearReferencesJdbc();
}
// Stop any threads the web application started
clearReferencesThreads();
// Check for leaks triggered by ThreadLocals loaded by this class loader
if (clearReferencesThreadLocals && !JreCompat.isGraalAvailable()) {
checkThreadLocalsForLeaks();
}
// Clear RMI Targets loaded by this class loader
if (clearReferencesRmiTargets) {
clearReferencesRmiTargets();
}
// Clear the IntrospectionUtils cache.
IntrospectionUtils.clear();
// Clear the classloader reference in common-logging
if (clearReferencesLogFactoryRelease) {
LogFactory.release(this);
}
// Clear the classloader reference in the VM's bean introspector
java.beans.Introspector.flushCaches();
// Clear any custom URLStreamHandlers
TomcatURLStreamHandlerFactory.release(this);
}
/**
* Deregister any JDBC drivers registered by the webapp that the webapp forgot. This is made unnecessary complex
* because a) DriverManager checks the class loader of the calling class (it would be much easier if it checked the
* context class loader) b) using reflection would create a dependency on the DriverManager implementation which
* can, and has, changed.
* <p>
* We can't just create an instance of JdbcLeakPrevention as it will be loaded by the common class loader (since
* it's .class file is in the $CATALINA_HOME/lib directory). This would fail DriverManager's check on the class
* loader of the calling class. So, we load the bytes via our parent class loader but define the class with this
* class loader so the JdbcLeakPrevention looks like a webapp class to the DriverManager.
* <p>
* If only apps cleaned up after themselves...
*/
private void clearReferencesJdbc() {
// We know roughly how big the class will be (~ 1K) so allow 2k as a
// starting point
byte[] classBytes = new byte[2048];
int offset = 0;
try (InputStream is = getResourceAsStream("org/apache/catalina/loader/JdbcLeakPrevention.class")) {
if (is == null) {
throw new FileNotFoundException("org/apache/catalina/loader/JdbcLeakPrevention.class");
}
int read = is.read(classBytes, offset, classBytes.length - offset);
while (read > -1) {
offset += read;
if (offset == classBytes.length) {
// Buffer full - double size
byte[] tmp = new byte[classBytes.length * 2];
System.arraycopy(classBytes, 0, tmp, 0, classBytes.length);
classBytes = tmp;
}
read = is.read(classBytes, offset, classBytes.length - offset);
}
Class<?> lpClass = defineClass("org.apache.catalina.loader.JdbcLeakPrevention", classBytes, 0, offset,
this.getClass().getProtectionDomain());
Object obj = lpClass.getConstructor().newInstance();
@SuppressWarnings("unchecked")
List<String> driverNames =
(List<String>) obj.getClass().getMethod("clearJdbcDriverRegistrations").invoke(obj);
for (String name : driverNames) {
log.warn(sm.getString("webappClassLoader.clearJdbc", getContextName(), name));
}
} catch (Exception e) {
// So many things to go wrong above...
Throwable t = ExceptionUtils.unwrapInvocationTargetException(e);
ExceptionUtils.handleThrowable(t);
log.warn(sm.getString("webappClassLoader.jdbcRemoveFailed", getContextName()), t);
}
}
private void clearReferencesThreads() {
Thread[] threads = getThreads();
List<Thread> threadsToStop = new ArrayList<>();
// Iterate over the set of threads
for (Thread thread : threads) {
if (thread != null) {
ClassLoader ccl = thread.getContextClassLoader();
if (ccl == this) {
// Don't warn about this thread
if (thread == Thread.currentThread()) {
continue;
}
final String threadName = thread.getName();
// JVM controlled threads
ThreadGroup tg = thread.getThreadGroup();
if (tg != null && JVM_THREAD_GROUP_NAMES.contains(tg.getName())) {
// HttpClient keep-alive threads
if (clearReferencesHttpClientKeepAliveThread && threadName.equals("Keep-Alive-Timer")) {
thread.setContextClassLoader(parent);
log.debug(sm.getString("webappClassLoader.checkThreadsHttpClient"));
}
// Don't warn about remaining JVM controlled threads
continue;
}
// Skip threads that have already died
if (!thread.isAlive()) {
continue;
}
// TimerThread can be stopped safely so treat separately
// "java.util.TimerThread" in Sun/Oracle JDK
// "java.util.Timer$TimerImpl" in Apache Harmony and in IBM JDK
if (thread.getClass().getName().startsWith("java.util.Timer") && clearReferencesStopTimerThreads) {
clearReferencesStopTimerThread(thread);
continue;
}
if (isRequestThread(thread)) {
log.warn(sm.getString("webappClassLoader.stackTraceRequestThread", getContextName(), threadName,
getStackTrace(thread)));
} else {
log.warn(sm.getString("webappClassLoader.stackTrace", getContextName(), threadName,
getStackTrace(thread)));
}
// Don't try and stop the threads unless explicitly
// configured to do so
if (!clearReferencesStopThreads) {
continue;
}
// If the thread has been started via an executor, try
// shutting down the executor
boolean usingExecutor = false;
try {
Object executor = getExecutor(thread);
if (executor instanceof ThreadPoolExecutor) {
((ThreadPoolExecutor) executor).shutdownNow();
usingExecutor = true;
} else if (executor instanceof java.util.concurrent.ThreadPoolExecutor) {
((java.util.concurrent.ThreadPoolExecutor) executor).shutdownNow();
usingExecutor = true;
}
} catch (SecurityException | NoSuchFieldException | IllegalArgumentException |
IllegalAccessException | InaccessibleObjectException e) {
log.warn(sm.getString("webappClassLoader.stopThreadFail", thread.getName(), getContextName()),
e);
}
// Stopping an executor automatically interrupts the
// associated threads. For non-executor threads, interrupt
// them here.
if (!usingExecutor && !thread.isInterrupted()) {
thread.interrupt();
}
// Threads are expected to take a short time to stop after
// being interrupted. Make a note of all threads that are
// expected to stop to enable them to be checked at the end
// of this method.
threadsToStop.add(thread);
}
}
}
// If thread stopping is enabled, threads should have been stopped above
// when the executor was shut down or the thread was interrupted but
// that depends on the thread correctly handling the interrupt. Check
// each thread and if any are still running give all threads up to a
// total of 2 seconds to shut down.
int count = 0;
for (Thread t : threadsToStop) {
while (t.isAlive() && count < 100) {
try {
Thread.sleep(20);
} catch (InterruptedException e) {
// Quit the while loop
break;
}
count++;
}
if (t.isAlive()) {
// Unable to stop the thread. Log an error.
log.error(sm.getString("webappClassLoader.stopThreadFail", t.getName(), getContextName()));
}
}
}
private Object getExecutor(Thread thread)
throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException {
Object result = null;
// Runnable wrapped by Thread
// "target" in Sun/Oracle JDK
// "runnable" in IBM JDK
// "action" in Apache Harmony
Object target = null;
for (String fieldName : new String[] { "target", "runnable", "action" }) {
try {
Field targetField = thread.getClass().getDeclaredField(fieldName);
targetField.setAccessible(true);
target = targetField.get(thread);
break;
} catch (NoSuchFieldException nfe) {
// Ignore
}
}
// "java.util.concurrent" code is in public domain,
// so all implementations are similar including our
// internal fork.
if (target != null && target.getClass().getCanonicalName() != null && (target.getClass().getCanonicalName()
.equals("org.apache.tomcat.util.threads.ThreadPoolExecutor.Worker") ||
target.getClass().getCanonicalName().equals("java.util.concurrent.ThreadPoolExecutor.Worker"))) {
Field executorField = target.getClass().getDeclaredField("this$0");
executorField.setAccessible(true);
result = executorField.get(target);
}
if (result == null) {
Object holder;
Object task;
try {
Field holderField = thread.getClass().getDeclaredField("holder");
holderField.setAccessible(true);
holder = holderField.get(thread);
Field taskField = holder.getClass().getDeclaredField("task");
taskField.setAccessible(true);
task = taskField.get(holder);
} catch (NoSuchFieldException nfe) {
return null;
}
if (task != null && task.getClass().getCanonicalName() != null && (task.getClass().getCanonicalName()
.equals("org.apache.tomcat.util.threads.ThreadPoolExecutor.Worker") ||
task.getClass().getCanonicalName().equals("java.util.concurrent.ThreadPoolExecutor.Worker"))) {
Field executorField = task.getClass().getDeclaredField("this$0");
executorField.setAccessible(true);
result = executorField.get(task);
}
}
return result;
}
/*
* Look at a threads stack trace to see if it is a request thread or not. It isn't perfect, but it should be
* good-enough for most cases.
*/
private boolean isRequestThread(Thread thread) {
StackTraceElement[] elements = thread.getStackTrace();
if (elements.length == 0) {
// Must have stopped already. Too late to ignore it. Assume not a
// request processing thread.
return false;
}
// Step through the methods in reverse order looking for calls to any
// CoyoteAdapter method. All request threads will have this unless
// Tomcat has been heavily modified - in which case there isn't much we
// can do.
for (int i = 0; i < elements.length; i++) {
StackTraceElement element = elements[elements.length - (i + 1)];
if ("org.apache.catalina.connector.CoyoteAdapter".equals(element.getClassName())) {
return true;
}
}
return false;
}
private void clearReferencesStopTimerThread(Thread thread) {
// Need to get references to:
// in Sun/Oracle JDK:
// - newTasksMayBeScheduled field (in java.util.TimerThread)
// - queue field
// - queue.clear()
// in IBM JDK, Apache Harmony:
// - cancel() method (in java.util.Timer$TimerImpl)
try {
try {
Field newTasksMayBeScheduledField = thread.getClass().getDeclaredField("newTasksMayBeScheduled");
newTasksMayBeScheduledField.setAccessible(true);
Field queueField = thread.getClass().getDeclaredField("queue");
queueField.setAccessible(true);
Object queue = queueField.get(thread);
Method clearMethod = queue.getClass().getDeclaredMethod("clear");
clearMethod.setAccessible(true);
synchronized (queue) {
newTasksMayBeScheduledField.setBoolean(thread, false);
clearMethod.invoke(queue);
// In case queue was already empty. Should only be one
// thread waiting but use notifyAll() to be safe.
queue.notifyAll();
}
} catch (NoSuchFieldException nfe) {
Method cancelMethod = thread.getClass().getDeclaredMethod("cancel");
synchronized (thread) {
cancelMethod.setAccessible(true);
cancelMethod.invoke(thread);
}
}
log.warn(sm.getString("webappClassLoader.warnTimerThread", getContextName(), thread.getName()));
} catch (Exception e) {
// So many things to go wrong above...
Throwable t = ExceptionUtils.unwrapInvocationTargetException(e);
ExceptionUtils.handleThrowable(t);
log.warn(sm.getString("webappClassLoader.stopTimerThreadFail", thread.getName(), getContextName()), t);
}
}
private void checkThreadLocalsForLeaks() {
Thread[] threads = getThreads();
try {
// Make the fields in the Thread class that store ThreadLocals
// accessible
Field threadLocalsField = Thread.class.getDeclaredField("threadLocals");
threadLocalsField.setAccessible(true);
Field inheritableThreadLocalsField = Thread.class.getDeclaredField("inheritableThreadLocals");
inheritableThreadLocalsField.setAccessible(true);
// Make the underlying array of ThreadLoad.ThreadLocalMap.Entry objects
// accessible
Class<?> tlmClass = Class.forName("java.lang.ThreadLocal$ThreadLocalMap");
Field tableField = tlmClass.getDeclaredField("table");
tableField.setAccessible(true);
Method expungeStaleEntriesMethod = tlmClass.getDeclaredMethod("expungeStaleEntries");
expungeStaleEntriesMethod.setAccessible(true);
for (Thread thread : threads) {
Object threadLocalMap;
if (thread != null) {
// Clear the first map
threadLocalMap = threadLocalsField.get(thread);
if (null != threadLocalMap) {
expungeStaleEntriesMethod.invoke(threadLocalMap);
checkThreadLocalMapForLeaks(threadLocalMap, tableField);
}
// Clear the second map
threadLocalMap = inheritableThreadLocalsField.get(thread);
if (null != threadLocalMap) {
expungeStaleEntriesMethod.invoke(threadLocalMap);
checkThreadLocalMapForLeaks(threadLocalMap, tableField);
}
}
}
} catch (InaccessibleObjectException e) {
// Must be running on without the necessary command line options.
log.warn(sm.getString("webappClassLoader.addExportsThreadLocal", getCurrentModuleName()));
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
log.warn(sm.getString("webappClassLoader.checkThreadLocalsForLeaksFail", getContextName()), t);
}
}
/**
* Analyzes the given thread local map object. Also pass in the field that points to the internal table to save
* re-calculating it on every call to this method.
*/
private void checkThreadLocalMapForLeaks(Object map, Field internalTableField)
throws IllegalAccessException, NoSuchFieldException {
if (map != null) {
Object[] table = (Object[]) internalTableField.get(map);
if (table != null) {
for (Object obj : table) {
if (obj != null) {
boolean keyLoadedByWebapp = false;
boolean valueLoadedByWebapp = false;
// Check the key
Object key = ((Reference<?>) obj).get();
if (this.equals(key) || loadedByThisOrChild(key)) {
keyLoadedByWebapp = true;
}
// Check the value
Field valueField = obj.getClass().getDeclaredField("value");
valueField.setAccessible(true);
Object value = valueField.get(obj);
if (this.equals(value) || loadedByThisOrChild(value)) {
valueLoadedByWebapp = true;
}
if (keyLoadedByWebapp || valueLoadedByWebapp) {
Object[] args = new Object[5];
args[0] = getContextName();
if (key != null) {
args[1] = getPrettyClassName(key.getClass());
try {
args[2] = key.toString();
} catch (Exception e) {
log.warn(
sm.getString("webappClassLoader.checkThreadLocalsForLeaks.badKey", args[1]),
e);
args[2] = sm.getString("webappClassLoader.checkThreadLocalsForLeaks.unknown");
}
}
if (value != null) {
args[3] = getPrettyClassName(value.getClass());
try {
args[4] = value.toString();
} catch (Exception e) {
log.warn(sm.getString("webappClassLoader.checkThreadLocalsForLeaks.badValue",
args[3]), e);
args[4] = sm.getString("webappClassLoader.checkThreadLocalsForLeaks.unknown");
}
}
if (valueLoadedByWebapp) {
log.error(sm.getString("webappClassLoader.checkThreadLocalsForLeaks", args));
} else if (value == null) {
if (log.isDebugEnabled()) {
log.debug(sm.getString("webappClassLoader.checkThreadLocalsForLeaksNull", args));
}
} else {
if (log.isDebugEnabled()) {
log.debug(sm.getString("webappClassLoader.checkThreadLocalsForLeaksNone", args));
}
}
}
}
}
}
}
}
private String getPrettyClassName(Class<?> clazz) {
String name = clazz.getCanonicalName();
if (name == null) {
name = clazz.getName();
}
return name;
}
private String getStackTrace(Thread thread) {
StringBuilder builder = new StringBuilder();
for (StackTraceElement ste : thread.getStackTrace()) {
builder.append("\n ").append(ste);
}
return builder.toString();
}
/**
* @param o object to test, may be null
*
* @return <code>true</code> if o has been loaded by the current classloader or one of its descendants.
*/
private boolean loadedByThisOrChild(Object o) {
if (o == null) {
return false;
}
Class<?> clazz;
if (o instanceof Class) {
clazz = (Class<?>) o;
} else {
clazz = o.getClass();
}
ClassLoader cl = clazz.getClassLoader();
while (cl != null) {
if (cl == this) {
return true;
}
cl = cl.getParent();
}
if (o instanceof Collection<?>) {
try {
for (Object entry : (Collection<?>) o) {
if (loadedByThisOrChild(entry)) {
return true;
}
}
} catch (ConcurrentModificationException e) {
log.warn(sm.getString("webappClassLoader.loadedByThisOrChildFail", clazz.getName(), getContextName()),
e);
}
}
return false;
}
/**
* @return the current threads as an array.
*/
private Thread[] getThreads() {
// Get the current thread group
ThreadGroup tg = Thread.currentThread().getThreadGroup();
// Find the root thread group
try {
while (tg.getParent() != null) {
tg = tg.getParent();
}
} catch (SecurityException se) {
String msg = sm.getString("webappClassLoader.getThreadGroupError", tg.getName());
if (log.isDebugEnabled()) {
log.debug(msg, se);
} else {
log.warn(msg);
}
}
int threadCountGuess = tg.activeCount() + 50;
Thread[] threads = new Thread[threadCountGuess];
int threadCountActual = tg.enumerate(threads);
// Make sure we don't miss any threads
while (threadCountActual == threadCountGuess) {
threadCountGuess *= 2;
threads = new Thread[threadCountGuess];
// Note tg.enumerate(Thread[]) silently ignores any threads that
// can't fit into the array
threadCountActual = tg.enumerate(threads);
}
return threads;
}
/**
* This depends on the internals of the Sun JVM so it does everything by reflection.
*/
private void clearReferencesRmiTargets() {
try {
// Need access to the ccl field of sun.rmi.transport.Target to find
// the leaks
Class<?> objectTargetClass = Class.forName("sun.rmi.transport.Target");
Field cclField = objectTargetClass.getDeclaredField("ccl");
cclField.setAccessible(true);
// Need access to the stub field to report the leaks
Field stubField = objectTargetClass.getDeclaredField("stub");
stubField.setAccessible(true);
// Clear the objTable map
Class<?> objectTableClass = Class.forName("sun.rmi.transport.ObjectTable");
Field objTableField = objectTableClass.getDeclaredField("objTable");
objTableField.setAccessible(true);
Object objTable = objTableField.get(null);
if (objTable == null) {
return;
}
Field tableLockField = objectTableClass.getDeclaredField("tableLock");
tableLockField.setAccessible(true);
Object tableLock = tableLockField.get(null);
synchronized (tableLock) {
// Iterate over the values in the table
if (objTable instanceof Map<?,?>) {
Iterator<?> iter = ((Map<?,?>) objTable).values().iterator();
while (iter.hasNext()) {
Object obj = iter.next();
Object cclObject = cclField.get(obj);
if (this == cclObject) {
iter.remove();
Object stubObject = stubField.get(obj);
log.error(sm.getString("webappClassLoader.clearRmi", stubObject.getClass().getName(),
stubObject));
}
}
}
// Clear the implTable map
Field implTableField = objectTableClass.getDeclaredField("implTable");
implTableField.setAccessible(true);
Object implTable = implTableField.get(null);
if (implTable == null) {
return;
}
// Iterate over the values in the table
if (implTable instanceof Map<?,?>) {
Iterator<?> iter = ((Map<?,?>) implTable).values().iterator();
while (iter.hasNext()) {
Object obj = iter.next();
Object cclObject = cclField.get(obj);
if (this == cclObject) {
iter.remove();
}
}
}
}
} catch (ClassNotFoundException e) {
log.info(sm.getString("webappClassLoader.clearRmiInfo", getContextName()), e);
} catch (SecurityException | NoSuchFieldException | IllegalArgumentException | IllegalAccessException e) {
log.warn(sm.getString("webappClassLoader.clearRmiFail", getContextName()), e);
} catch (InaccessibleObjectException e) {
// Must be running on without the necessary command line options.
log.warn(sm.getString("webappClassLoader.addExportsRmi", getCurrentModuleName()));
}
}
private String getCurrentModuleName() {
String moduleName = this.getClass().getModule().getName();
if (moduleName == null) {
moduleName = "ALL-UNNAMED";
}
return moduleName;
}
/**
* Find specified class in local repositories.
*
* @param name The binary name of the class to be loaded
*
* @return the loaded class, or null if the class isn't found
*/
protected Class<?> findClassInternal(String name) {
checkStateForResourceLoading(name);
if (name == null) {
return null;
}
String path = binaryNameToPath(name, true);
return findClassInternal(name, path);
}
/*
* The use of getPackage() is appropriate given that the code is checking if the package is sealed. Therefore,
* parent class loaders need to be checked.
*/
@SuppressWarnings("deprecation")
private Class<?> findClassInternal(String name, String path) {
ResourceEntry entry = resourceEntries.get(path);
WebResource resource = null;
if (entry == null) {
resource = resources.getClassLoaderResource(path);
if (!resource.exists()) {
return null;
}
entry = new ResourceEntry();
entry.lastModified = resource.getLastModified();
// Add the entry in the local resource repository
synchronized (resourceEntries) {
// Ensures that all the threads which may be in a race to load
// a particular class all end up with the same ResourceEntry
// instance
ResourceEntry entry2 = resourceEntries.get(path);
if (entry2 == null) {
resourceEntries.put(path, entry);
} else {
entry = entry2;
}
}
}
Class<?> clazz = entry.loadedClass;
if (clazz != null) {
return clazz;
}
synchronized (JreCompat.isGraalAvailable() ? this : getClassLoadingLock(name)) {
clazz = entry.loadedClass;
if (clazz != null) {
return clazz;
}
if (resource == null) {
resource = resources.getClassLoaderResource(path);
}
if (!resource.exists()) {
return null;
}
byte[] binaryContent = resource.getContent();
if (binaryContent == null) {
// Something went wrong reading the class bytes (and will have
// been logged at debug level).
return null;
}
Manifest manifest = resource.getManifest();
URL codeBase = resource.getCodeBase();
Certificate[] certificates = resource.getCertificates();
if (!transformers.isEmpty()) {
// If the resource is a class just being loaded, decorate it
// with any attached transformers
// Ignore leading '/' and trailing CLASS_FILE_SUFFIX
// Should be cheaper than replacing '.' by '/' in class name.
String internalName = path.substring(1, path.length() - CLASS_FILE_SUFFIX.length());
for (ClassFileTransformer transformer : this.transformers) {
try {
byte[] transformed = transformer.transform(this, internalName, null, null, binaryContent);
if (transformed != null) {
binaryContent = transformed;
}
} catch (IllegalClassFormatException e) {
log.error(sm.getString("webappClassLoader.transformError", name), e);
return null;
}
}
}
// Looking up the package
String packageName = null;
int pos = name.lastIndexOf('.');
if (pos != -1) {
packageName = name.substring(0, pos);
}
Package pkg;
if (packageName != null) {
pkg = getPackage(packageName);
// Define the package (if null)
if (pkg == null) {
try {
if (manifest == null) {
definePackage(packageName, null, null, null, null, null, null, null);
} else {
definePackage(packageName, manifest, codeBase);
}
} catch (IllegalArgumentException e) {
// Ignore: normal error due to dual definition of package
}
pkg = getPackage(packageName);
}
}
try {
clazz = defineClass(name, binaryContent, 0, binaryContent.length,
new CodeSource(codeBase, certificates));
} catch (UnsupportedClassVersionError ucve) {
throw new UnsupportedClassVersionError(
ucve.getLocalizedMessage() + " " + sm.getString("webappClassLoader.wrongVersion", name));
} catch (LinkageError e) {
// May be caused by the transformation also triggering loading of the class - BZ 68721
try {
// Try and load the already defined class
clazz = findLoadedClass0(name);
} catch (Throwable t) {
// Not BZ 68721
ExceptionUtils.handleThrowable(t);
// Re-throw the original exception
throw e;
}
if (clazz == null) {
// Not BZ 68721
throw e;
}
}
entry.loadedClass = clazz;
}
return clazz;
}
private String binaryNameToPath(String binaryName, boolean withLeadingSlash) {
// 1 for leading '/', 6 for ".class"
StringBuilder path = new StringBuilder(7 + binaryName.length());
if (withLeadingSlash) {
path.append('/');
}
path.append(binaryName.replace('.', '/'));
path.append(CLASS_FILE_SUFFIX);
return path.toString();
}
private String nameToPath(String name) {
StringBuilder path = new StringBuilder(1 + name.length());
path.append('/');
path.append(name);
return path.toString();
}
/**
* Returns true if the specified package name is sealed according to the given manifest.
*
* @param name Path name to check
* @param man Associated manifest
*
* @return <code>true</code> if the manifest associated says it is sealed
*/
protected boolean isPackageSealed(String name, Manifest man) {
String path = name.replace('.', '/') + '/';
Attributes attr = man.getAttributes(path);
String sealed = null;
if (attr != null) {
sealed = attr.getValue(Name.SEALED);
}
if (sealed == null) {
if ((attr = man.getMainAttributes()) != null) {
sealed = attr.getValue(Name.SEALED);
}
}
return "true".equalsIgnoreCase(sealed);
}
/**
* Finds the class with the given name if it has previously been loaded and cached by this class loader, and return
* the Class object. If this class has not been cached, return <code>null</code>.
*
* @param name The binary name of the resource to return
*
* @return a loaded class
*/
protected Class<?> findLoadedClass0(String name) {
String path = binaryNameToPath(name, true);
ResourceEntry entry = resourceEntries.get(path);
if (entry != null) {
return entry.loadedClass;
}
return null;
}
/**
* Filter classes.
*
* @param name class name
* @param isClassName <code>true</code> if name is a class name, <code>false</code> if name is a resource name
*
* @return <code>true</code> if the class should be filtered
*/
protected boolean filter(String name, boolean isClassName) {
if (name == null) {
return false;
}
char ch;
if (name.startsWith("jakarta")) {
/* 7 == length("jakarta") */
if (name.length() == 7) {
return false;
}
ch = name.charAt(7);
if (isClassName && ch == '.') {
/* 8 == length("jakarta.") */
if (name.startsWith("servlet.jsp.jstl.", 8)) {
return false;
}
if (name.startsWith("annotation.", 8) || name.startsWith("el.", 8) || name.startsWith("servlet.", 8) ||
name.startsWith("websocket.", 8) || name.startsWith("security.auth.message.", 8)) {
return true;
}
} else if (!isClassName && ch == '/') {
/* 8 == length("jakarta/") */
if (name.startsWith("servlet/jsp/jstl/", 8)) {
return false;
}
if (name.startsWith("annotation/", 8) || name.startsWith("el/", 8) || name.startsWith("servlet/", 8) ||
name.startsWith("websocket/", 8) || name.startsWith("security/auth/message/", 8)) {
return true;
}
}
} else if (name.startsWith("javax")) {
/* 5 == length("javax") */
if (name.length() == 5) {
return false;
}
ch = name.charAt(5);
if (isClassName && ch == '.') {
/* 6 == length("javax.") */
if (name.startsWith("websocket.", 6)) {
return true;
}
} else if (!isClassName && ch == '/') {
/* 6 == length("javax/") */
if (name.startsWith("websocket/", 6)) {
return true;
}
}
} else if (name.startsWith("org")) {
/* 3 == length("org") */
if (name.length() == 3) {
return false;
}
ch = name.charAt(3);
if (isClassName && ch == '.') {
/* 4 == length("org.") */
if (name.startsWith("apache.", 4)) {
/* 11 == length("org.apache.") */
if (name.startsWith("tomcat.jdbc.", 11)) {
return false;
}
if (name.startsWith("el.", 11) || name.startsWith("catalina.", 11) ||
name.startsWith("jasper.", 11) || name.startsWith("juli.", 11) ||
name.startsWith("tomcat.", 11) || name.startsWith("naming.", 11) ||
name.startsWith("coyote.", 11)) {
return true;
}
}
} else if (!isClassName && ch == '/') {
/* 4 == length("org/") */
if (name.startsWith("apache/", 4)) {
/* 11 == length("org/apache/") */
if (name.startsWith("tomcat/jdbc/", 11)) {
return false;
}
if (name.startsWith("el/", 11) || name.startsWith("catalina/", 11) ||
name.startsWith("jasper/", 11) || name.startsWith("juli/", 11) ||
name.startsWith("tomcat/", 11) || name.startsWith("naming/", 11) ||
name.startsWith("coyote/", 11)) {
return true;
}
}
}
}
return false;
}
@Override
protected void addURL(URL url) {
super.addURL(url);
hasExternalRepositories = true;
// Clear the not found resources as they may now be available at the added URL.
notFoundClassResources.clear();
}
@Override
public String getWebappName() {
return getContextName();
}
@Override
public String getHostName() {
if (resources != null) {
Container host = resources.getContext().getParent();
if (host != null) {
return host.getName();
}
}
return null;
}
@Override
public String getServiceName() {
if (resources != null) {
Container host = resources.getContext().getParent();
if (host != null) {
Container engine = host.getParent();
if (engine != null) {
return engine.getName();
}
}
}
return null;
}
private static class CombinedEnumeration implements Enumeration<URL> {
private final Enumeration<URL>[] sources;
private int index = 0;
CombinedEnumeration(Enumeration<URL> enum1, Enumeration<URL> enum2) {
@SuppressWarnings("unchecked")
Enumeration<URL>[] sources = new Enumeration[] { enum1, enum2 };
this.sources = sources;
}
@Override
public boolean hasMoreElements() {
return inc();
}
@Override
public URL nextElement() {
if (inc()) {
return sources[index].nextElement();
}
throw new NoSuchElementException();
}
private boolean inc() {
while (index < sources.length) {
if (sources[index].hasMoreElements()) {
return true;
}
index++;
}
return false;
}
}
}