Class WebappClassLoaderBase
- All Implemented Interfaces:
Closeable
,AutoCloseable
,Lifecycle
,WebappProperties
,InstrumentableClassLoader
- 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 - 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
-
Nested Class Summary
Modifier and TypeClassDescriptionprotected class
protected static final class
protected final class
Nested classes/interfaces inherited from interface org.apache.catalina.Lifecycle
Lifecycle.SingleUse
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Field Summary
Modifier and TypeFieldDescriptionprotected boolean
Should 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 ClassLoader
The 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 WebResourceRoot
Associated web resources for this webapp.protected static final StringManager
The 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
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Constructor Summary
ModifierConstructorDescriptionprotected
Construct a new ClassLoader with no defined repositories and no parent ClassLoader.protected
WebappClassLoaderBase
(ClassLoader parent) Construct a new ClassLoader with no defined repositories and the given parent ClassLoader. -
Method Summary
Modifier and TypeMethodDescriptionvoid
addLifecycleListener
(LifecycleListener listener) Add a LifecycleEvent listener to this component.void
addTransformer
(ClassFileTransformer transformer) Adds the specified class file transformer to this class loader.protected void
protected void
checkStateForClassLoading
(String className) protected void
checkStateForResourceLoading
(String resource) protected void
Clear references.protected void
void
destroy()
Prepare to discard the object.protected final Class
<?> doDefineClass
(String name, byte[] b, int off, int len, ProtectionDomain protectionDomain) protected boolean
Filter 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 life cycle listeners associated with this life cycle.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 aURL
referring to it, ornull
if this resource cannot be found.findResources
(String name) boolean
boolean
boolean
boolean
boolean
boolean
boolean
Return 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 ClassLoader
protected PermissionCollection
getPermissions
(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.boolean
getState()
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.boolean
Enables 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.void
init()
Prepare the component for starting.protected boolean
isPackageSealed
(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.boolean
modified()
Have one or more classes or resources been modified so that a reload is appropriate?void
removeLifecycleListener
(LifecycleListener listener) Remove a LifecycleEvent listener from this component.void
removeTransformer
(ClassFileTransformer transformer) Removes the specified class file transformer from this class loader.void
setClearReferencesHttpClientKeepAliveThread
(boolean clearReferencesHttpClientKeepAliveThread) Set the clearReferencesHttpClientKeepAliveThread feature for this Context.void
setClearReferencesLogFactoryRelease
(boolean clearReferencesLogFactoryRelease) Set the clearReferencesLogFactoryRelease feature for this Context.void
setClearReferencesRmiTargets
(boolean clearReferencesRmiTargets) void
setClearReferencesStopThreads
(boolean clearReferencesStopThreads) Set the clearReferencesStopThreads feature for this Context.void
setClearReferencesStopTimerThreads
(boolean clearReferencesStopTimerThreads) Set the clearReferencesStopTimerThreads feature for this Context.void
setClearReferencesThreadLocals
(boolean clearReferencesThreadLocals) void
setDelegate
(boolean delegate) Set the "delegate first" flag for this class loader.protected void
setJavaseClassLoader
(ClassLoader classLoader) void
setResources
(WebResourceRoot resources) Set associated resources.void
setSkipMemoryLeakChecksOnJvmShutdown
(boolean skipMemoryLeakChecksOnJvmShutdown) void
start()
Prepare for the beginning of active use of the public methods other than property getters/setters and life cycle methods of this component.void
stop()
Gracefully terminate the active use of the public methods other than property getters/setters and life cycle methods of this component.toString()
Methods inherited from class java.net.URLClassLoader
close, definePackage, newInstance, newInstance
Methods inherited from class java.security.SecureClassLoader
defineClass, defineClass
Methods 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, setSigners
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods 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. -
parent
The parent class loader.
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Constructor Details
-
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.
-
getDelegate
public boolean getDelegate()Return the "delegate first" flag for this class loader.- Returns:
true
if 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.
-
setClearReferencesStopThreads
public void setClearReferencesStopThreads(boolean clearReferencesStopThreads) Set the clearReferencesStopThreads feature for this Context.- Parameters:
clearReferencesStopThreads
- The new flag value
-
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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getClearReferencesThreadLocals
public boolean getClearReferencesThreadLocals() -
setClearReferencesThreadLocals
public void setClearReferencesThreadLocals(boolean clearReferencesThreadLocals) -
getSkipMemoryLeakChecksOnJvmShutdown
public boolean getSkipMemoryLeakChecksOnJvmShutdown() -
setSkipMemoryLeakChecksOnJvmShutdown
public void setSkipMemoryLeakChecksOnJvmShutdown(boolean skipMemoryLeakChecksOnJvmShutdown) -
addTransformer
Description copied from interface:InstrumentableClassLoader
Adds the specified class file transformer to this class loader. The transformer will then be able to instrument the bytecode of any classes loaded by this class loader after the invocation of this method.- Specified by:
addTransformer
in interfaceInstrumentableClassLoader
- Parameters:
transformer
- The transformer to add to the class loader
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removeTransformer
Description copied from interface:InstrumentableClassLoader
Removes the specified class file transformer from this class loader. It will no longer be able to instrument the byte code of any classes loaded by the class loader after the invocation of this method. However, any classes already instrumented by this transformer before this method call will remain in their instrumented state.- Specified by:
removeTransformer
in 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:
true
if 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:
findClass
in 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 aURL
referring to it, ornull
if this resource cannot be found.- Overrides:
findResource
in classURLClassLoader
- Parameters:
name
- Name of the resource to be found
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findResources
- Overrides:
findResources
in classURLClassLoader
- Throws:
IOException
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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
delegate
property 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:
getResource
in classClassLoader
- Parameters:
name
- Name of the resource to return a URL for
- If the
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getResources
- Overrides:
getResources
in 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:
getResourceAsStream
in 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)
withfalse
as the second argument.- Overrides:
loadClass
in 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 sameClass
object is returned. - If the
delegate
property 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.
resolve
flag istrue
, this method will then callresolveClass(Class)
on the resulting Class object.- Overrides:
loadClass
in classClassLoader
- Parameters:
name
- The binary name of the class to be loadedresolve
- Iftrue
then resolve the class- Throws:
ClassNotFoundException
- if the class was not found
- Call
-
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:
getPermissions
in classURLClassLoader
- Parameters:
codeSource
- where the code was loaded from- Returns:
- PermissionCollection for CodeSource
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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
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.- Overrides:
getURLs
in classURLClassLoader
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addLifecycleListener
Description copied from interface:Lifecycle
Add a LifecycleEvent listener to this component.- Specified by:
addLifecycleListener
in interfaceLifecycle
- Parameters:
listener
- The listener to add
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findLifecycleListeners
Description copied from interface:Lifecycle
Get the life cycle listeners associated with this life cycle.- Specified by:
findLifecycleListeners
in 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
Description copied from interface:Lifecycle
Remove a LifecycleEvent listener from this component.- Specified by:
removeLifecycleListener
in interfaceLifecycle
- Parameters:
listener
- The listener to remove
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getState
Description copied from interface:Lifecycle
Obtain the current state of the source component. -
getStateName
Description copied from interface:Lifecycle
Obtain 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:
getStateName
in interfaceLifecycle
- Returns:
- The name of the current component state.
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init
public void init()Description copied from interface:Lifecycle
Prepare the component for starting. This method should perform any initialization required post object creation. The followingLifecycleEvent
s will be fired in the following order:- INIT_EVENT: On the successful completion of component initialization.
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start
Description copied from interface:Lifecycle
Prepare for the beginning of active use of the public methods other than property getters/setters and life cycle methods of this component. This method should be called before any of the public methods other than property getters/setters and life cycle methods of this component are utilized. The followingLifecycleEvent
s will be fired in the following order:- BEFORE_START_EVENT: At the beginning of the method. It is as this point the state transitions to
LifecycleState.STARTING_PREP
. - START_EVENT: During the method once it is safe to call start() for any child components. It is at this point
that the state transitions to
LifecycleState.STARTING
and that the public methods other than property getters/setters and life cycle methods may be used. - AFTER_START_EVENT: At the end of the method, immediately before it returns. It is at this point that the
state transitions to
LifecycleState.STARTED
.
- Specified by:
start
in interfaceLifecycle
- Throws:
LifecycleException
- if this component detects a fatal error that prevents this component from being used
- BEFORE_START_EVENT: At the beginning of the method. It is as this point the state transitions to
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stop
Description copied from interface:Lifecycle
Gracefully terminate the active use of the public methods other than property getters/setters and life cycle methods of this component. Once the STOP_EVENT is fired, the public methods other than property getters/setters and life cycle methods should not be used. The followingLifecycleEvent
s will be fired in the following order:- BEFORE_STOP_EVENT: At the beginning of the method. It is at this point that the state transitions to
LifecycleState.STOPPING_PREP
. - STOP_EVENT: During the method once it is safe to call stop() for any child components. It is at this point
that the state transitions to
LifecycleState.STOPPING
and that the public methods other than property getters/setters and life cycle methods may no longer be used. - AFTER_STOP_EVENT: At the end of the method, immediately before it returns. It is at this point that the state
transitions to
LifecycleState.STOPPED
.
LifecycleState.FAILED
then the three events above will be fired but the component will transition directly fromLifecycleState.FAILED
toLifecycleState.STOPPING
, bypassingLifecycleState.STOPPING_PREP
- Specified by:
stop
in interfaceLifecycle
- Throws:
LifecycleException
- if this component detects a fatal error that needs to be reported
- BEFORE_STOP_EVENT: At the beginning of the method. It is at this point that the state transitions to
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destroy
public void destroy()Description copied from interface:Lifecycle
Prepare to discard the object. The followingLifecycleEvent
s 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
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isPackageSealed
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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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filter
Filter classes.- Parameters:
name
- class nameisClassName
-true
if name is a class name,false
if name is a resource name- Returns:
true
if the class should be filtered
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addURL
- Overrides:
addURL
in classURLClassLoader
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getWebappName
Description copied from interface:WebappProperties
Returns a name for the logging system to use for the web application, if any, associated with the class loader.- Specified by:
getWebappName
in 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:WebappProperties
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.- Specified by:
getHostName
in 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:WebappProperties
Returns 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:
getServiceName
in 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:WebappProperties
Enables 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:
hasLoggingConfig
in interfaceWebappProperties
- Returns:
true
if the web application includes a logging configuration at the standard location of /WEB-INF/classes/logging.properties.
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