java/org/apache/catalina/loader/WebappLoader.java - tomcat - Git at Google

 /*
  * 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.beans.PropertyChangeListener;
 import java.beans.PropertyChangeSupport;
 import java.io.File;
 import java.lang.reflect.Constructor;
 import java.net.URL;
 import java.net.URLClassLoader;
 import java.nio.charset.StandardCharsets;

 import javax.management.ObjectName;

 import jakarta.servlet.ServletContext;

 import org.apache.catalina.Context;
 import org.apache.catalina.Globals;
 import org.apache.catalina.LifecycleException;
 import org.apache.catalina.LifecycleState;
 import org.apache.catalina.Loader;
 import org.apache.catalina.util.LifecycleMBeanBase;
 import org.apache.catalina.util.ToStringUtil;
 import org.apache.juli.logging.Log;
 import org.apache.juli.logging.LogFactory;
 import org.apache.tomcat.jakartaee.ClassConverter;
 import org.apache.tomcat.jakartaee.EESpecProfile;
 import org.apache.tomcat.jakartaee.EESpecProfiles;
 import org.apache.tomcat.util.ExceptionUtils;
 import org.apache.tomcat.util.buf.UDecoder;
 import org.apache.tomcat.util.compat.JreCompat;
 import org.apache.tomcat.util.modeler.Registry;
 import org.apache.tomcat.util.res.StringManager;

 /**
  * Classloader implementation which is specialized for handling web applications in the most efficient way, while being
  * Catalina aware (all accesses to resources are made through {@link org.apache.catalina.WebResourceRoot}). This class
  * loader supports detection of modified Java classes, which can be used to implement auto-reload support.
  * <p>
  * This class loader is configured via the Resources children of its Context prior to calling <code>start()</code>. When
  * a new class is required, these Resources will be consulted first to locate the class. If it is not present, the
  * system class loader will be used instead.
  *
  * @author Craig R. McClanahan
  * @author Remy Maucherat
  */
 public class WebappLoader extends LifecycleMBeanBase implements Loader {

     private static final Log log = LogFactory.getLog(WebappLoader.class);

     // ----------------------------------------------------- Instance Variables

     /**
      * The class loader being managed by this Loader component.
      */
     private WebappClassLoaderBase classLoader = null;


     /**
      * The Context with which this Loader has been associated.
      */
     private Context context = null;


     /**
      * The "follow standard delegation model" flag that will be used to configure our ClassLoader.
      */
     private boolean delegate = false;


     /**
      * The profile name which will be used by the converter, or null if not used. Any invalid profile value will default
      * to the TOMCAT profile, which converts all packages used by Tomcat.
      */
     private String jakartaConverter = null;


     /**
      * The Java class name of the ClassLoader implementation to be used. This class should extend WebappClassLoaderBase,
      * otherwise, a different loader implementation must be used.
      */
     private String loaderClass = ParallelWebappClassLoader.class.getName();


     /**
      * The string manager for this package.
      */
     protected static final StringManager sm = StringManager.getManager(WebappLoader.class);


     /**
      * The property change support for this component.
      */
     protected final PropertyChangeSupport support = new PropertyChangeSupport(this);


     /**
      * Classpath set in the loader.
      */
     private String classpath = null;


     // ------------------------------------------------------------- Properties

     /**
      * Return the Java class loader to be used by this Container.
      */
     @Override
     public ClassLoader getClassLoader() {
         return classLoader;
     }


     @Override
     public Context getContext() {
         return context;
     }


     @Override
     public void setContext(Context context) {

         if (this.context == context) {
             return;
         }

         if (getState().isAvailable()) {
             throw new IllegalStateException(sm.getString("webappLoader.setContext.ise"));
         }

         // Process this property change
         Context oldContext = this.context;
         this.context = context;
         support.firePropertyChange("context", oldContext, this.context);
     }


     /**
      * Return the "follow standard delegation model" flag used to configure our ClassLoader.
      */
     @Override
     public boolean getDelegate() {
         return this.delegate;
     }


     /**
      * Set the "follow standard delegation model" flag used to configure our ClassLoader.
      *
      * @param delegate The new flag
      */
     @Override
     public void setDelegate(boolean delegate) {
         boolean oldDelegate = this.delegate;
         this.delegate = delegate;
         support.firePropertyChange("delegate", Boolean.valueOf(oldDelegate), Boolean.valueOf(this.delegate));
     }


     /**
      * @return a non null String if the loader will attempt to use the Jakarta converter. The String is the name of the
      *             profile used for conversion.
      */
     public String getJakartaConverter() {
         return jakartaConverter;
     }


     /**
      * Set the Jakarta converter.
      *
      * @param jakartaConverter The profile name which will be used by the converter Any invalid profile value will
      *                             default to the TOMCAT profile, which converts all packages used by Tomcat.
      */
     public void setJakartaConverter(String jakartaConverter) {
         String oldJakartaConverter = this.jakartaConverter;
         this.jakartaConverter = jakartaConverter;
         support.firePropertyChange("jakartaConverter", oldJakartaConverter, this.jakartaConverter);
     }


     /**
      * @return the ClassLoader class name.
      */
     public String getLoaderClass() {
         return this.loaderClass;
     }


     /**
      * Set the ClassLoader class name.
      *
      * @param loaderClass The new ClassLoader class name
      */
     public void setLoaderClass(String loaderClass) {
         this.loaderClass = loaderClass;
     }

     /**
      * Set the ClassLoader instance, without relying on reflection This method will also invoke
      * {@link #setLoaderClass(String)} with {@code loaderInstance.getClass().getName()} as an argument
      *
      * @param loaderInstance The new ClassLoader instance to use
      */
     public void setLoaderInstance(WebappClassLoaderBase loaderInstance) {
         this.classLoader = loaderInstance;
         setLoaderClass(loaderInstance.getClass().getName());
     }

     // --------------------------------------------------------- Public Methods

     /**
      * Add a property change listener to this component.
      *
      * @param listener The listener to add
      */
     @Override
     public void addPropertyChangeListener(PropertyChangeListener listener) {

         support.addPropertyChangeListener(listener);

     }


     /**
      * Execute a periodic task, such as reloading, etc. This method will be invoked inside the classloading context of
      * this container. Unexpected throwables will be caught and logged.
      */
     @Override
     public void backgroundProcess() {
         Context context = getContext();
         if (context != null) {
             if (context.getReloadable() && modified()) {
                 Thread currentThread = Thread.currentThread();
                 ClassLoader originalTccl = currentThread.getContextClassLoader();
                 try {
                     currentThread.setContextClassLoader(WebappLoader.class.getClassLoader());
                     context.reload();
                 } finally {
                     currentThread.setContextClassLoader(originalTccl);
                 }
             }
         }
     }


     public String[] getLoaderRepositories() {
         if (classLoader == null) {
             return new String[0];
         }
         URL[] urls = classLoader.getURLs();
         String[] result = new String[urls.length];
         for (int i = 0; i < urls.length; i++) {
             result[i] = urls[i].toExternalForm();
         }
         return result;
     }

     public String getLoaderRepositoriesString() {
         String repositories[] = getLoaderRepositories();
         StringBuilder sb = new StringBuilder();
         for (String repository : repositories) {
             sb.append(repository).append(':');
         }
         return sb.toString();
     }


     /**
      * Classpath, as set in org.apache.catalina.jsp_classpath context property
      *
      * @return The classpath
      */
     public String getClasspath() {
         return classpath;
     }


     /**
      * Has the internal repository associated with this Loader been modified, such that the loaded classes should be
      * reloaded?
      */
     @Override
     public boolean modified() {
         return classLoader != null ? classLoader.modified() : false;
     }


     /**
      * Remove a property change listener from this component.
      *
      * @param listener The listener to remove
      */
     @Override
     public void removePropertyChangeListener(PropertyChangeListener listener) {
         support.removePropertyChangeListener(listener);
     }


     /**
      * Return a String representation of this component.
      */
     @Override
     public String toString() {
         return ToStringUtil.toString(this, context);
     }


     /**
      * Start associated {@link ClassLoader} and implement the requirements of
      * {@link org.apache.catalina.util.LifecycleBase#startInternal()}.
      *
      * @exception LifecycleException if this component detects a fatal error that prevents this component from being
      *                                   used
      */
     @Override
     protected void startInternal() throws LifecycleException {

         if (log.isDebugEnabled()) {
             log.debug(sm.getString("webappLoader.starting"));
         }

         if (context.getResources() == null) {
             log.info(sm.getString("webappLoader.noResources", context));
             setState(LifecycleState.STARTING);
             return;
         }

         // Construct a class loader based on our current repositories list
         try {

             classLoader = createClassLoader();
             classLoader.setResources(context.getResources());
             classLoader.setDelegate(this.delegate);

             // Set Jakarta class converter
             if (getJakartaConverter() != null) {
                 MigrationUtil.addJakartaEETransformer(classLoader, getJakartaConverter());
             }

             // Configure our repositories
             setClassPath();

             classLoader.start();

             String contextName = context.getName();
             if (!contextName.startsWith("/")) {
                 contextName = "/" + contextName;
             }
             ObjectName cloname =
                     new ObjectName(context.getDomain() + ":type=" + classLoader.getClass().getSimpleName() + ",host=" +
                             context.getParent().getName() + ",context=" + contextName);
             Registry.getRegistry(null, null).registerComponent(classLoader, cloname, null);

         } catch (Throwable t) {
             t = ExceptionUtils.unwrapInvocationTargetException(t);
             ExceptionUtils.handleThrowable(t);
             throw new LifecycleException(sm.getString("webappLoader.startError"), t);
         }

         setState(LifecycleState.STARTING);
     }


     /**
      * Stop associated {@link ClassLoader} and implement the requirements of
      * {@link org.apache.catalina.util.LifecycleBase#stopInternal()}.
      *
      * @exception LifecycleException if this component detects a fatal error that prevents this component from being
      *                                   used
      */
     @Override
     protected void stopInternal() throws LifecycleException {

         if (log.isDebugEnabled()) {
             log.debug(sm.getString("webappLoader.stopping"));
         }

         setState(LifecycleState.STOPPING);

         // Remove context attributes as appropriate
         ServletContext servletContext = context.getServletContext();
         servletContext.removeAttribute(Globals.CLASS_PATH_ATTR);

         // Throw away our current class loader if any
         if (classLoader != null) {
             try {
                 classLoader.stop();
             } finally {
                 classLoader.destroy();
             }

             // classLoader must be non-null to have been registered
             try {
                 String contextName = context.getName();
                 if (!contextName.startsWith("/")) {
                     contextName = "/" + contextName;
                 }
                 ObjectName cloname =
                         new ObjectName(context.getDomain() + ":type=" + classLoader.getClass().getSimpleName() +
                                 ",host=" + context.getParent().getName() + ",context=" + contextName);
                 Registry.getRegistry(null, null).unregisterComponent(cloname);
             } catch (Exception e) {
                 log.warn(sm.getString("webappLoader.stopError"), e);
             }
         }


         classLoader = null;
     }


     // ------------------------------------------------------- Private Methods

     /**
      * Create associated classLoader.
      */
     private WebappClassLoaderBase createClassLoader() throws Exception {

         if (classLoader != null) {
             return classLoader;
         }

         if (ParallelWebappClassLoader.class.getName().equals(loaderClass)) {
             return new ParallelWebappClassLoader(context.getParentClassLoader());
         }

         Class<?> clazz = Class.forName(loaderClass);
         WebappClassLoaderBase classLoader = null;

         ClassLoader parentClassLoader = context.getParentClassLoader();

         Class<?>[] argTypes = { ClassLoader.class };
         Object[] args = { parentClassLoader };
         Constructor<?> constr = clazz.getConstructor(argTypes);
         classLoader = (WebappClassLoaderBase) constr.newInstance(args);

         return classLoader;
     }


     /**
      * Set the appropriate context attribute for our class path. This is required only because Jasper depends on it.
      */
     private void setClassPath() {

         // Validate our current state information
         if (context == null) {
             return;
         }
         ServletContext servletContext = context.getServletContext();
         if (servletContext == null) {
             return;
         }

         StringBuilder classpath = new StringBuilder();

         // Assemble the class path information from our class loader chain
         ClassLoader loader = getClassLoader();

         if (delegate && loader != null) {
             // Skip the webapp loader for now as delegation is enabled
             loader = loader.getParent();
         }

         while (loader != null) {
             if (!buildClassPath(classpath, loader)) {
                 break;
             }
             loader = loader.getParent();
         }

         if (delegate) {
             // Delegation was enabled, go back and add the webapp paths
             loader = getClassLoader();
             if (loader != null) {
                 buildClassPath(classpath, loader);
             }
         }

         this.classpath = classpath.toString();

         // Store the assembled class path as a servlet context attribute
         servletContext.setAttribute(Globals.CLASS_PATH_ATTR, this.classpath);
     }


     private boolean buildClassPath(StringBuilder classpath, ClassLoader loader) {
         if (loader instanceof URLClassLoader) {
             URL repositories[] = ((URLClassLoader) loader).getURLs();
             for (URL url : repositories) {
                 String repository = url.toString();
                 if (repository.startsWith("file://")) {
                     repository = UDecoder.URLDecode(repository.substring(7), StandardCharsets.UTF_8);
                 } else if (repository.startsWith("file:")) {
                     repository = UDecoder.URLDecode(repository.substring(5), StandardCharsets.UTF_8);
                 } else {
                     continue;
                 }
                 if (repository == null) {
                     continue;
                 }
                 if (classpath.length() > 0) {
                     classpath.append(File.pathSeparator);
                 }
                 classpath.append(repository);
             }
         } else if (loader == ClassLoader.getSystemClassLoader()) {
             // From Java 9 the internal class loaders no longer extend
             // URLCLassLoader
             String cp = System.getProperty("java.class.path");
             if (cp != null && cp.length() > 0) {
                 if (classpath.length() > 0) {
                     classpath.append(File.pathSeparator);
                 }
                 classpath.append(cp);
             }
             return false;
         } else {
             // Ignore Graal "unknown" classloader
             if (!JreCompat.isGraalAvailable()) {
                 log.info(sm.getString("webappLoader.unknownClassLoader", loader, loader.getClass()));
             }
             return false;
         }
         return true;
     }

     @Override
     protected String getDomainInternal() {
         return context.getDomain();
     }


     @Override
     protected String getObjectNameKeyProperties() {

         StringBuilder name = new StringBuilder("type=Loader");

         name.append(",host=");
         name.append(context.getParent().getName());

         name.append(",context=");

         String contextName = context.getName();
         if (!contextName.startsWith("/")) {
             name.append('/');
         }
         name.append(contextName);

         return name.toString();
     }


     /*
      * Implemented in a sub-class so EESpecProfile and EESpecProfiles are not loaded unless a profile is configured.
      * Otherwise, tomcat-embed-core.jar has a runtime dependency on the migration tool whether it is used or not.
      */
     private static class MigrationUtil {

         public static void addJakartaEETransformer(WebappClassLoaderBase webappClassLoader, String profileName) {
             EESpecProfile profile = null;
             try {
                 profile = EESpecProfiles.valueOf(profileName);
             } catch (IllegalArgumentException ignored) {
                 // Use default value
                 log.warn(sm.getString("webappLoader.unknownProfile", profileName));
             }
             webappClassLoader.addTransformer(profile != null ? new ClassConverter(profile) : new ClassConverter());
         }
     }
 }
	/*
	* 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.beans.PropertyChangeListener;
	import java.beans.PropertyChangeSupport;
	import java.io.File;
	import java.lang.reflect.Constructor;
	import java.net.URL;
	import java.net.URLClassLoader;
	import java.nio.charset.StandardCharsets;

	import javax.management.ObjectName;

	import jakarta.servlet.ServletContext;

	import org.apache.catalina.Context;
	import org.apache.catalina.Globals;
	import org.apache.catalina.LifecycleException;
	import org.apache.catalina.LifecycleState;
	import org.apache.catalina.Loader;
	import org.apache.catalina.util.LifecycleMBeanBase;
	import org.apache.catalina.util.ToStringUtil;
	import org.apache.juli.logging.Log;
	import org.apache.juli.logging.LogFactory;
	import org.apache.tomcat.jakartaee.ClassConverter;
	import org.apache.tomcat.jakartaee.EESpecProfile;
	import org.apache.tomcat.jakartaee.EESpecProfiles;
	import org.apache.tomcat.util.ExceptionUtils;
	import org.apache.tomcat.util.buf.UDecoder;
	import org.apache.tomcat.util.compat.JreCompat;
	import org.apache.tomcat.util.modeler.Registry;
	import org.apache.tomcat.util.res.StringManager;

	/**
	* Classloader implementation which is specialized for handling web applications in the most efficient way, while being
	* Catalina aware (all accesses to resources are made through {@link org.apache.catalina.WebResourceRoot}). This class
	* loader supports detection of modified Java classes, which can be used to implement auto-reload support.
	* <p>
	* This class loader is configured via the Resources children of its Context prior to calling <code>start()</code>. When
	* a new class is required, these Resources will be consulted first to locate the class. If it is not present, the
	* system class loader will be used instead.
	*
	* @author Craig R. McClanahan
	* @author Remy Maucherat
	*/
	public class WebappLoader extends LifecycleMBeanBase implements Loader {

	private static final Log log = LogFactory.getLog(WebappLoader.class);

	// ----------------------------------------------------- Instance Variables

	/**
	* The class loader being managed by this Loader component.
	*/
	private WebappClassLoaderBase classLoader = null;


	/**
	* The Context with which this Loader has been associated.
	*/
	private Context context = null;


	/**
	* The "follow standard delegation model" flag that will be used to configure our ClassLoader.
	*/
	private boolean delegate = false;


	/**
	* The profile name which will be used by the converter, or null if not used. Any invalid profile value will default
	* to the TOMCAT profile, which converts all packages used by Tomcat.
	*/
	private String jakartaConverter = null;


	/**
	* The Java class name of the ClassLoader implementation to be used. This class should extend WebappClassLoaderBase,
	* otherwise, a different loader implementation must be used.
	*/
	private String loaderClass = ParallelWebappClassLoader.class.getName();


	/**
	* The string manager for this package.
	*/
	protected static final StringManager sm = StringManager.getManager(WebappLoader.class);


	/**
	* The property change support for this component.
	*/
	protected final PropertyChangeSupport support = new PropertyChangeSupport(this);


	/**
	* Classpath set in the loader.
	*/
	private String classpath = null;


	// ------------------------------------------------------------- Properties

	/**
	* Return the Java class loader to be used by this Container.
	*/
	@Override
	public ClassLoader getClassLoader() {
	return classLoader;
	}


	@Override
	public Context getContext() {
	return context;
	}


	@Override
	public void setContext(Context context) {

	if (this.context == context) {
	return;
	}

	if (getState().isAvailable()) {
	throw new IllegalStateException(sm.getString("webappLoader.setContext.ise"));
	}

	// Process this property change
	Context oldContext = this.context;
	this.context = context;
	support.firePropertyChange("context", oldContext, this.context);
	}


	/**
	* Return the "follow standard delegation model" flag used to configure our ClassLoader.
	*/
	@Override
	public boolean getDelegate() {
	return this.delegate;
	}


	/**
	* Set the "follow standard delegation model" flag used to configure our ClassLoader.
	*
	* @param delegate The new flag
	*/
	@Override
	public void setDelegate(boolean delegate) {
	boolean oldDelegate = this.delegate;
	this.delegate = delegate;
	support.firePropertyChange("delegate", Boolean.valueOf(oldDelegate), Boolean.valueOf(this.delegate));
	}


	/**
	* @return a non null String if the loader will attempt to use the Jakarta converter. The String is the name of the
	* profile used for conversion.
	*/
	public String getJakartaConverter() {
	return jakartaConverter;
	}


	/**
	* Set the Jakarta converter.
	*
	* @param jakartaConverter The profile name which will be used by the converter Any invalid profile value will
	* default to the TOMCAT profile, which converts all packages used by Tomcat.
	*/
	public void setJakartaConverter(String jakartaConverter) {
	String oldJakartaConverter = this.jakartaConverter;
	this.jakartaConverter = jakartaConverter;
	support.firePropertyChange("jakartaConverter", oldJakartaConverter, this.jakartaConverter);
	}


	/**
	* @return the ClassLoader class name.
	*/
	public String getLoaderClass() {
	return this.loaderClass;
	}


	/**
	* Set the ClassLoader class name.
	*
	* @param loaderClass The new ClassLoader class name
	*/
	public void setLoaderClass(String loaderClass) {
	this.loaderClass = loaderClass;
	}

	/**
	* Set the ClassLoader instance, without relying on reflection This method will also invoke
	* {@link #setLoaderClass(String)} with {@code loaderInstance.getClass().getName()} as an argument
	*
	* @param loaderInstance The new ClassLoader instance to use
	*/
	public void setLoaderInstance(WebappClassLoaderBase loaderInstance) {
	this.classLoader = loaderInstance;
	setLoaderClass(loaderInstance.getClass().getName());
	}

	// --------------------------------------------------------- Public Methods

	/**
	* Add a property change listener to this component.
	*
	* @param listener The listener to add
	*/
	@Override
	public void addPropertyChangeListener(PropertyChangeListener listener) {

	support.addPropertyChangeListener(listener);

	}


	/**
	* Execute a periodic task, such as reloading, etc. This method will be invoked inside the classloading context of
	* this container. Unexpected throwables will be caught and logged.
	*/
	@Override
	public void backgroundProcess() {
	Context context = getContext();
	if (context != null) {
	if (context.getReloadable() && modified()) {
	Thread currentThread = Thread.currentThread();
	ClassLoader originalTccl = currentThread.getContextClassLoader();
	try {
	currentThread.setContextClassLoader(WebappLoader.class.getClassLoader());
	context.reload();
	} finally {
	currentThread.setContextClassLoader(originalTccl);
	}
	}
	}
	}


	public String[] getLoaderRepositories() {
	if (classLoader == null) {
	return new String[0];
	}
	URL[] urls = classLoader.getURLs();
	String[] result = new String[urls.length];
	for (int i = 0; i < urls.length; i++) {
	result[i] = urls[i].toExternalForm();
	}
	return result;
	}

	public String getLoaderRepositoriesString() {
	String repositories[] = getLoaderRepositories();
	StringBuilder sb = new StringBuilder();
	for (String repository : repositories) {
	sb.append(repository).append(':');
	}
	return sb.toString();
	}


	/**
	* Classpath, as set in org.apache.catalina.jsp_classpath context property
	*
	* @return The classpath
	*/
	public String getClasspath() {
	return classpath;
	}


	/**
	* Has the internal repository associated with this Loader been modified, such that the loaded classes should be
	* reloaded?
	*/
	@Override
	public boolean modified() {
	return classLoader != null ? classLoader.modified() : false;
	}


	/**
	* Remove a property change listener from this component.
	*
	* @param listener The listener to remove
	*/
	@Override
	public void removePropertyChangeListener(PropertyChangeListener listener) {
	support.removePropertyChangeListener(listener);
	}


	/**
	* Return a String representation of this component.
	*/
	@Override
	public String toString() {
	return ToStringUtil.toString(this, context);
	}


	/**
	* Start associated {@link ClassLoader} and implement the requirements of
	* {@link org.apache.catalina.util.LifecycleBase#startInternal()}.
	*
	* @exception LifecycleException if this component detects a fatal error that prevents this component from being
	* used
	*/
	@Override
	protected void startInternal() throws LifecycleException {

	if (log.isDebugEnabled()) {
	log.debug(sm.getString("webappLoader.starting"));
	}

	if (context.getResources() == null) {
	log.info(sm.getString("webappLoader.noResources", context));
	setState(LifecycleState.STARTING);
	return;
	}

	// Construct a class loader based on our current repositories list
	try {

	classLoader = createClassLoader();
	classLoader.setResources(context.getResources());
	classLoader.setDelegate(this.delegate);

	// Set Jakarta class converter
	if (getJakartaConverter() != null) {
	MigrationUtil.addJakartaEETransformer(classLoader, getJakartaConverter());
	}

	// Configure our repositories
	setClassPath();

	classLoader.start();

	String contextName = context.getName();
	if (!contextName.startsWith("/")) {
	contextName = "/" + contextName;
	}
	ObjectName cloname =
	new ObjectName(context.getDomain() + ":type=" + classLoader.getClass().getSimpleName() + ",host=" +
	context.getParent().getName() + ",context=" + contextName);
	Registry.getRegistry(null, null).registerComponent(classLoader, cloname, null);

	} catch (Throwable t) {
	t = ExceptionUtils.unwrapInvocationTargetException(t);
	ExceptionUtils.handleThrowable(t);
	throw new LifecycleException(sm.getString("webappLoader.startError"), t);
	}

	setState(LifecycleState.STARTING);
	}


	/**
	* Stop associated {@link ClassLoader} and implement the requirements of
	* {@link org.apache.catalina.util.LifecycleBase#stopInternal()}.
	*
	* @exception LifecycleException if this component detects a fatal error that prevents this component from being
	* used
	*/
	@Override
	protected void stopInternal() throws LifecycleException {

	if (log.isDebugEnabled()) {
	log.debug(sm.getString("webappLoader.stopping"));
	}

	setState(LifecycleState.STOPPING);

	// Remove context attributes as appropriate
	ServletContext servletContext = context.getServletContext();
	servletContext.removeAttribute(Globals.CLASS_PATH_ATTR);

	// Throw away our current class loader if any
	if (classLoader != null) {
	try {
	classLoader.stop();
	} finally {
	classLoader.destroy();
	}

	// classLoader must be non-null to have been registered
	try {
	String contextName = context.getName();
	if (!contextName.startsWith("/")) {
	contextName = "/" + contextName;
	}
	ObjectName cloname =
	new ObjectName(context.getDomain() + ":type=" + classLoader.getClass().getSimpleName() +
	",host=" + context.getParent().getName() + ",context=" + contextName);
	Registry.getRegistry(null, null).unregisterComponent(cloname);
	} catch (Exception e) {
	log.warn(sm.getString("webappLoader.stopError"), e);
	}
	}


	classLoader = null;
	}


	// ------------------------------------------------------- Private Methods

	/**
	* Create associated classLoader.
	*/
	private WebappClassLoaderBase createClassLoader() throws Exception {

	if (classLoader != null) {
	return classLoader;
	}

	if (ParallelWebappClassLoader.class.getName().equals(loaderClass)) {
	return new ParallelWebappClassLoader(context.getParentClassLoader());
	}

	Class<?> clazz = Class.forName(loaderClass);
	WebappClassLoaderBase classLoader = null;

	ClassLoader parentClassLoader = context.getParentClassLoader();

	Class<?>[] argTypes = { ClassLoader.class };
	Object[] args = { parentClassLoader };
	Constructor<?> constr = clazz.getConstructor(argTypes);
	classLoader = (WebappClassLoaderBase) constr.newInstance(args);

	return classLoader;
	}


	/**
	* Set the appropriate context attribute for our class path. This is required only because Jasper depends on it.
	*/
	private void setClassPath() {

	// Validate our current state information
	if (context == null) {
	return;
	}
	ServletContext servletContext = context.getServletContext();
	if (servletContext == null) {
	return;
	}

	StringBuilder classpath = new StringBuilder();

	// Assemble the class path information from our class loader chain
	ClassLoader loader = getClassLoader();

	if (delegate && loader != null) {
	// Skip the webapp loader for now as delegation is enabled
	loader = loader.getParent();
	}

	while (loader != null) {
	if (!buildClassPath(classpath, loader)) {
	break;
	}
	loader = loader.getParent();
	}

	if (delegate) {
	// Delegation was enabled, go back and add the webapp paths
	loader = getClassLoader();
	if (loader != null) {
	buildClassPath(classpath, loader);
	}
	}

	this.classpath = classpath.toString();

	// Store the assembled class path as a servlet context attribute
	servletContext.setAttribute(Globals.CLASS_PATH_ATTR, this.classpath);
	}


	private boolean buildClassPath(StringBuilder classpath, ClassLoader loader) {
	if (loader instanceof URLClassLoader) {
	URL repositories[] = ((URLClassLoader) loader).getURLs();
	for (URL url : repositories) {
	String repository = url.toString();
	if (repository.startsWith("file://")) {
	repository = UDecoder.URLDecode(repository.substring(7), StandardCharsets.UTF_8);
	} else if (repository.startsWith("file:")) {
	repository = UDecoder.URLDecode(repository.substring(5), StandardCharsets.UTF_8);
	} else {
	continue;
	}
	if (repository == null) {
	continue;
	}
	if (classpath.length() > 0) {
	classpath.append(File.pathSeparator);
	}
	classpath.append(repository);
	}
	} else if (loader == ClassLoader.getSystemClassLoader()) {
	// From Java 9 the internal class loaders no longer extend
	// URLCLassLoader
	String cp = System.getProperty("java.class.path");
	if (cp != null && cp.length() > 0) {
	if (classpath.length() > 0) {
	classpath.append(File.pathSeparator);
	}
	classpath.append(cp);
	}
	return false;
	} else {
	// Ignore Graal "unknown" classloader
	if (!JreCompat.isGraalAvailable()) {
	log.info(sm.getString("webappLoader.unknownClassLoader", loader, loader.getClass()));
	}
	return false;
	}
	return true;
	}

	@Override
	protected String getDomainInternal() {
	return context.getDomain();
	}


	@Override
	protected String getObjectNameKeyProperties() {

	StringBuilder name = new StringBuilder("type=Loader");

	name.append(",host=");
	name.append(context.getParent().getName());

	name.append(",context=");

	String contextName = context.getName();
	if (!contextName.startsWith("/")) {
	name.append('/');
	}
	name.append(contextName);

	return name.toString();
	}


	/*
	* Implemented in a sub-class so EESpecProfile and EESpecProfiles are not loaded unless a profile is configured.
	* Otherwise, tomcat-embed-core.jar has a runtime dependency on the migration tool whether it is used or not.
	*/
	private static class MigrationUtil {

	public static void addJakartaEETransformer(WebappClassLoaderBase webappClassLoader, String profileName) {
	EESpecProfile profile = null;
	try {
	profile = EESpecProfiles.valueOf(profileName);
	} catch (IllegalArgumentException ignored) {
	// Use default value
	log.warn(sm.getString("webappLoader.unknownProfile", profileName));
	}
	webappClassLoader.addTransformer(profile != null ? new ClassConverter(profile) : new ClassConverter());
	}
	}
	}