Class WebappClassLoaderBase
- All Implemented Interfaces:
Closeable,AutoCloseable,Lifecycle,WebappProperties,InstrumentableClassLoader,PermissionCheck
- Direct Known Subclasses:
ParallelWebappClassLoader,WebappClassLoader
This class loader is a full reimplementation of the URLClassLoader from the JDK. It is designed to be
fully compatible with a normal URLClassLoader, although its internal behavior may be completely
different.
IMPLEMENTATION NOTE - 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 delegate property
allows an application to modify this behavior to move the parent class loader ahead of the local repositories.
IMPLEMENTATION NOTE - Due to limitations in Jasper compilation technology, any repository which contains classes from the servlet API will be ignored by the class loader.
IMPLEMENTATION NOTE - 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.
IMPLEMENTATION NOTE - Local repositories are searched in the order they are added via the initial constructor.
IMPLEMENTATION NOTE - No check for sealing violations or security is made unless a security manager is present.
IMPLEMENTATION NOTE - As of 8.0, this class loader implements 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, Craig R. McClanahan
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprotected classprotected static final classprotected final classNested classes/interfaces inherited from interface org.apache.catalina.Lifecycle
Lifecycle.SingleUse -
Field Summary
FieldsModifier and TypeFieldDescriptionprotected booleanShould this class loader delegate to the parent class loader before searching its own repositories (i.e. the usual Java2 delegation model)?protected final HashMap<String,PermissionCollection> The PermissionCollection for each CodeSource for a web application context.protected final ClassLoaderThe parent class loader.protected final ArrayList<Permission>A list of read File Permission's required if this loader is for a web application context.protected final Map<String,ResourceEntry> The cache of ResourceEntry for classes and resources we have loaded, keyed by resource path, not binary name.protected WebResourceRootAssociated web resources for this webapp.protected final SecurityManagerInstance of the SecurityManager installed.protected static final StringManagerThe string manager for this package.Fields inherited from interface org.apache.catalina.Lifecycle
AFTER_DESTROY_EVENT, AFTER_INIT_EVENT, AFTER_START_EVENT, AFTER_STOP_EVENT, BEFORE_DESTROY_EVENT, BEFORE_INIT_EVENT, BEFORE_START_EVENT, BEFORE_STOP_EVENT, CONFIGURE_START_EVENT, CONFIGURE_STOP_EVENT, PERIODIC_EVENT, START_EVENT, STOP_EVENT -
Constructor Summary
ConstructorsModifierConstructorDescriptionprotectedConstruct a new ClassLoader with no defined repositories and no parent ClassLoader.protectedWebappClassLoaderBase(ClassLoader parent) Construct a new ClassLoader with no defined repositories and the given parent ClassLoader. -
Method Summary
Modifier and TypeMethodDescriptionvoidaddLifecycleListener(LifecycleListener listener) Add a lifecycle event listener to this component.voidaddTransformer(ClassFileTransformer transformer) Adds the specified class file transformer to this class loader.protected voidbooleancheck(Permission permission) Does this component have the given permission?protected voidcheckStateForClassLoading(String className) protected voidcheckStateForResourceLoading(String resource) protected voidClear references.protected voidvoiddestroy()Prepare to discard the object.protected final Class<?>doDefineClass(String name, byte[] b, int off, int len, ProtectionDomain protectionDomain) protected booleanFilter classes.Class<?>Find the specified class in our local repositories, if possible.protected Class<?>findClassInternal(String name) Find specified class in local repositories.Get the lifecycle listeners associated with this lifecycle.protected Class<?>findLoadedClass0(String name) Finds the class with the given name if it has previously been loaded and cached by this class loader, and return the Class object.findResource(String name) Find the specified resource in our local repository, and return aURLreferring to it, ornullif this resource cannot be found.findResources(String name) Return an enumeration ofURLsrepresenting all of the resources with the given name.booleanbooleanbooleanbooleanbooleanbooleanbooleanbooleanReturn the "delegate first" flag for this class loader.Returns a name for the logging system to use for the Host where the web application, if any, associated with the class loader is deployed.protected ClassLoaderprotected PermissionCollectiongetPermissions(CodeSource codeSource) Get the Permissions for a CodeSource.getResource(String name) Find the resource with the given name.getResourceAsStream(String name) Find the resource with the given name, and return an input stream that can be used for reading it.getResources(String name) Returns a name for the logging system to use for the Service where the Host, if any, associated with the class loader is deployed.booleangetState()Obtain the current state of the source component.Obtain a textual representation of the current component state.URL[]getURLs()Returns a name for the logging system to use for the web application, if any, associated with the class loader.booleanEnables JULI to determine if the web application includes a local configuration without JULI having to look for the file which it may not have permission to do when running under a SecurityManager.voidinit()Prepare the component for starting.protected booleanisPackageSealed(String name, Manifest man) Returns true if the specified package name is sealed according to the given manifest.Class<?>Load the class with the specified name.Class<?>Load the class with the specified name, searching using the following algorithm until it finds and returns the class.booleanmodified()Have one or more classes or resources been modified so that a reload is appropriate?protected voidRefresh the system policy file, to pick up eventual changes.voidremoveLifecycleListener(LifecycleListener listener) Remove a lifecycle event listener from this component.voidremoveTransformer(ClassFileTransformer transformer) Removes the specified class file transformer from this class loader.voidsetClearReferencesHttpClientKeepAliveThread(boolean clearReferencesHttpClientKeepAliveThread) Set the clearReferencesHttpClientKeepAliveThread feature for this Context.voidsetClearReferencesLogFactoryRelease(boolean clearReferencesLogFactoryRelease) Set the clearReferencesLogFactoryRelease feature for this Context.voidsetClearReferencesObjectStreamClassCaches(boolean clearReferencesObjectStreamClassCaches) voidsetClearReferencesRmiTargets(boolean clearReferencesRmiTargets) voidsetClearReferencesStopThreads(boolean clearReferencesStopThreads) Set the clearReferencesStopThreads feature for this Context.voidsetClearReferencesStopTimerThreads(boolean clearReferencesStopTimerThreads) Set the clearReferencesStopTimerThreads feature for this Context.voidsetClearReferencesThreadLocals(boolean clearReferencesThreadLocals) voidsetDelegate(boolean delegate) Set the "delegate first" flag for this class loader.protected voidsetJavaseClassLoader(ClassLoader classLoader) voidsetResources(WebResourceRoot resources) Set associated resources.voidsetSkipMemoryLeakChecksOnJvmShutdown(boolean skipMemoryLeakChecksOnJvmShutdown) voidstart()Start the class loader.voidstop()Stop the class loader.toString()Methods inherited from class java.net.URLClassLoader
close, definePackage, newInstance, newInstanceMethods inherited from class java.security.SecureClassLoader
defineClass, defineClassMethods inherited from class java.lang.ClassLoader
clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findClass, findLibrary, findLoadedClass, findResource, findSystemClass, getClassLoadingLock, getDefinedPackage, getDefinedPackages, getName, getPackage, getPackages, getParent, getPlatformClassLoader, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, getUnnamedModule, isRegisteredAsParallelCapable, registerAsParallelCapable, resolveClass, resources, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSignersMethods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, waitMethods inherited from interface org.apache.tomcat.InstrumentableClassLoader
copyWithoutTransformers
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Field Details
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sm
The string manager for this package. -
resources
Associated web resources for this webapp. -
resourceEntries
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. -
delegate
protected boolean delegateShould this class loader delegate to the parent class loader before searching its own repositories (i.e. the usual Java2 delegation model)? If set tofalse, 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,false, is the behavior called for by the servlet specification. -
permissionList
A list of read File Permission's required if this loader is for a web application context. -
loaderPC
The PermissionCollection for each CodeSource for a web application context. -
securityManager
Instance of the SecurityManager installed. -
parent
The parent class loader.
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Constructor Details
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WebappClassLoaderBase
protected WebappClassLoaderBase()Construct a new ClassLoader with no defined repositories and no parent ClassLoader. -
WebappClassLoaderBase
Construct a new ClassLoader with no defined repositories and the given parent ClassLoader.Method is used via reflection - see
WebappLoader.createClassLoader()- Parameters:
parent- Our parent class loader
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Method Details
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setResources
Set associated resources.- Parameters:
resources- the resources from which the classloader will load the classes
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getContextName
- Returns:
- the context name for this class loader.
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getDelegate
public boolean getDelegate()Return the "delegate first" flag for this class loader.- Returns:
trueif the class lookup will delegate to the parent first. The default in Tomcat isfalse.
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setDelegate
public void setDelegate(boolean delegate) Set the "delegate first" flag for this class loader. If this flag is true, this class loader delegates to the parent class loader before searching its own repositories, as in an ordinary (non-servlet) chain of Java class loaders. If set tofalse(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.- Parameters:
delegate- The new "delegate first" flag
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getClearReferencesRmiTargets
public boolean getClearReferencesRmiTargets() -
setClearReferencesRmiTargets
public void setClearReferencesRmiTargets(boolean clearReferencesRmiTargets) -
getClearReferencesStopThreads
public boolean getClearReferencesStopThreads()- Returns:
- the clearReferencesStopThreads flag for this Context.
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setClearReferencesStopThreads
public void setClearReferencesStopThreads(boolean clearReferencesStopThreads) Set the clearReferencesStopThreads feature for this Context.- Parameters:
clearReferencesStopThreads- The new flag value
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getClearReferencesStopTimerThreads
public boolean getClearReferencesStopTimerThreads()- Returns:
- the clearReferencesStopTimerThreads flag for this Context.
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setClearReferencesStopTimerThreads
public void setClearReferencesStopTimerThreads(boolean clearReferencesStopTimerThreads) Set the clearReferencesStopTimerThreads feature for this Context.- Parameters:
clearReferencesStopTimerThreads- The new flag value
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getClearReferencesLogFactoryRelease
public boolean getClearReferencesLogFactoryRelease()- Returns:
- the clearReferencesLogFactoryRelease flag for this Context.
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setClearReferencesLogFactoryRelease
public void setClearReferencesLogFactoryRelease(boolean clearReferencesLogFactoryRelease) Set the clearReferencesLogFactoryRelease feature for this Context.- Parameters:
clearReferencesLogFactoryRelease- The new flag value
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getClearReferencesHttpClientKeepAliveThread
public boolean getClearReferencesHttpClientKeepAliveThread()- Returns:
- the clearReferencesHttpClientKeepAliveThread flag for this Context.
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setClearReferencesHttpClientKeepAliveThread
public void setClearReferencesHttpClientKeepAliveThread(boolean clearReferencesHttpClientKeepAliveThread) Set the clearReferencesHttpClientKeepAliveThread feature for this Context.- Parameters:
clearReferencesHttpClientKeepAliveThread- The new flag value
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getClearReferencesObjectStreamClassCaches
public boolean getClearReferencesObjectStreamClassCaches() -
setClearReferencesObjectStreamClassCaches
public void setClearReferencesObjectStreamClassCaches(boolean clearReferencesObjectStreamClassCaches) -
getClearReferencesThreadLocals
public boolean getClearReferencesThreadLocals() -
setClearReferencesThreadLocals
public void setClearReferencesThreadLocals(boolean clearReferencesThreadLocals) -
getSkipMemoryLeakChecksOnJvmShutdown
public boolean getSkipMemoryLeakChecksOnJvmShutdown() -
setSkipMemoryLeakChecksOnJvmShutdown
public void setSkipMemoryLeakChecksOnJvmShutdown(boolean skipMemoryLeakChecksOnJvmShutdown) -
addTransformer
Adds the specified class file transformer to this class loader. The transformer will then be able to modify the bytecode of any classes loaded by this class loader after the invocation of this method.- Specified by:
addTransformerin interfaceInstrumentableClassLoader- Parameters:
transformer- The transformer to add to the class loader
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removeTransformer
Removes the specified class file transformer from this class loader. It will no longer be able to modify the byte code of any classes loaded by the class loader after the invocation of this method. However, any classes already modified by this transformer will remain transformed.- Specified by:
removeTransformerin interfaceInstrumentableClassLoader- Parameters:
transformer- The transformer to remove
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copyStateWithoutTransformers
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modified
public boolean modified()Have one or more classes or resources been modified so that a reload is appropriate?- Returns:
trueif there's been a modification
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toString
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doDefineClass
protected final Class<?> doDefineClass(String name, byte[] b, int off, int len, ProtectionDomain protectionDomain) -
findClass
Find the specified class in our local repositories, if possible. If not found, throwClassNotFoundException.- Overrides:
findClassin classURLClassLoader- Parameters:
name- The binary name of the class to be loaded- Throws:
ClassNotFoundException- if the class was not found
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findResource
Find the specified resource in our local repository, and return aURLreferring to it, ornullif this resource cannot be found.- Overrides:
findResourcein classURLClassLoader- Parameters:
name- Name of the resource to be found
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findResources
Return an enumeration ofURLsrepresenting all of the resources with the given name. If no resources with this name are found, return an empty enumeration.- Overrides:
findResourcesin classURLClassLoader- Parameters:
name- Name of the resources to be found- Throws:
IOException- if an input/output error occurs
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getResource
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, returnnull.This method searches according to the following algorithm, returning as soon as it finds the appropriate URL. If the resource cannot be found, returns
null.- If the
delegateproperty is set totrue, call thegetResource()method of the parent class loader, if any. - Call
findResource()to find this resource in our locally defined repositories. - Call the
getResource()method of the parent class loader, if any.
- Overrides:
getResourcein classClassLoader- Parameters:
name- Name of the resource to return a URL for
- If the
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getResources
- Overrides:
getResourcesin classClassLoader- Throws:
IOException
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getResourceAsStream
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 forgetResource(), after checking to see if the resource data has been previously cached. If the resource cannot be found, returnnull.- Overrides:
getResourceAsStreamin classURLClassLoader- Parameters:
name- Name of the resource to return an input stream for
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loadClass
Load the class with the specified name. This method searches for classes in the same manner asloadClass(String, boolean)withfalseas the second argument.- Overrides:
loadClassin classClassLoader- Parameters:
name- The binary name of the class to be loaded- Throws:
ClassNotFoundException- if the class was not found
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loadClass
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, returnsClassNotFoundException.- Call
findLoadedClass(String)to check if the class has already been loaded. If it has, the sameClassobject is returned. - If the
delegateproperty is set totrue, call theloadClass()method of the parent class loader, if any. - Call
findClass()to find this class in our locally defined repositories. - Call the
loadClass()method of our parent class loader, if any.
resolveflag istrue, this method will then callresolveClass(Class)on the resulting Class object.- Overrides:
loadClassin classClassLoader- Parameters:
name- The binary name of the class to be loadedresolve- Iftruethen resolve the class- Throws:
ClassNotFoundException- if the class was not found
- Call
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checkStateForClassLoading
- Throws:
ClassNotFoundException
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checkStateForResourceLoading
- Throws:
IllegalStateException
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getPermissions
Get the Permissions for a CodeSource. If this instance of WebappClassLoaderBase is for a web application context, add read FilePermission for the appropriate resources.- Overrides:
getPermissionsin classURLClassLoader- Parameters:
codeSource- where the code was loaded from- Returns:
- PermissionCollection for CodeSource
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check
Description copied from interface:PermissionCheckDoes this component have the given permission?- Specified by:
checkin interfacePermissionCheck- Parameters:
permission- The permission to test- Returns:
falseif a SecurityManager is enabled and the component does not have the given permission, otherwisetrue
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getURLs
Note that list of URLs returned by this method may not be complete. The web application class loader accesses class loader resources via the
WebResourceRootwhich 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.- Overrides:
getURLsin classURLClassLoader
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addLifecycleListener
Add a lifecycle event listener to this component.- Specified by:
addLifecycleListenerin interfaceLifecycle- Parameters:
listener- The listener to add
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findLifecycleListeners
Get the lifecycle listeners associated with this lifecycle. If this Lifecycle has no listeners registered, a zero-length array is returned.- Specified by:
findLifecycleListenersin interfaceLifecycle- Returns:
- An array containing the life cycle listeners associated with this life cycle. If this component has no listeners registered, a zero-length array is returned.
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removeLifecycleListener
Remove a lifecycle event listener from this component.- Specified by:
removeLifecycleListenerin interfaceLifecycle- Parameters:
listener- The listener to remove
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getState
Obtain the current state of the source component. -
getStateName
Description copied from interface:LifecycleObtain a textual representation of the current component state. Useful for JMX. The format of this string may vary between point releases and should not be relied upon to determine component state. To determine component state, useLifecycle.getState().- Specified by:
getStateNamein interfaceLifecycle- Returns:
- The name of the current component state.
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init
public void init()Description copied from interface:LifecyclePrepare the component for starting. This method should perform any initialization required post object creation. The followingLifecycleEvents will be fired in the following order:- INIT_EVENT: On the successful completion of component initialization.
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start
Start the class loader.- Specified by:
startin interfaceLifecycle- Throws:
LifecycleException- if a lifecycle error occurs
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stop
Stop the class loader.- Specified by:
stopin interfaceLifecycle- Throws:
LifecycleException- if a lifecycle error occurs
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destroy
public void destroy()Description copied from interface:LifecyclePrepare to discard the object. The followingLifecycleEvents will be fired in the following order:- DESTROY_EVENT: On the successful completion of component destruction.
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getJavaseClassLoader
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setJavaseClassLoader
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clearReferences
protected void clearReferences()Clear references. -
findClassInternal
Find specified class in local repositories.- Parameters:
name- The binary name of the class to be loaded- Returns:
- the loaded class, or null if the class isn't found
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isPackageSealed
Returns true if the specified package name is sealed according to the given manifest.- Parameters:
name- Path name to checkman- Associated manifest- Returns:
trueif the manifest associated says it is sealed
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findLoadedClass0
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, returnnull.- Parameters:
name- The binary name of the resource to return- Returns:
- a loaded class
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refreshPolicy
protected void refreshPolicy()Refresh the system policy file, to pick up eventual changes. -
filter
Filter classes.- Parameters:
name- class nameisClassName-trueif name is a class name,falseif name is a resource name- Returns:
trueif the class should be filtered
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addURL
- Overrides:
addURLin classURLClassLoader
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getWebappName
Description copied from interface:WebappPropertiesReturns a name for the logging system to use for the web application, if any, associated with the class loader.- Specified by:
getWebappNamein interfaceWebappProperties- Returns:
- The name to use for the web application or null if none is available.
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getHostName
Description copied from interface:WebappPropertiesReturns a name for the logging system to use for the Host where the web application, if any, associated with the class loader is deployed.- Specified by:
getHostNamein interfaceWebappProperties- Returns:
- The name to use for the Host where the web application is deployed or null if none is available.
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getServiceName
Description copied from interface:WebappPropertiesReturns a name for the logging system to use for the Service where the Host, if any, associated with the class loader is deployed.- Specified by:
getServiceNamein interfaceWebappProperties- Returns:
- The name to use for the Service where the Host is deployed or null if none is available.
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hasLoggingConfig
public boolean hasLoggingConfig()Description copied from interface:WebappPropertiesEnables JULI to determine if the web application includes a local configuration without JULI having to look for the file which it may not have permission to do when running under a SecurityManager.- Specified by:
hasLoggingConfigin interfaceWebappProperties- Returns:
trueif the web application includes a logging configuration at the standard location of /WEB-INF/classes/logging.properties.
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