If a ClassLoader does not implement this interface, then all the classes obtained from it should be considered as not reloadable (i.e. cacheable).
- Juergen Hoeller
Method SummaryModifier and TypeMethodDescription
default ClassLoaderReturn the original ClassLoader for this SmartClassLoader, or potentially the present loader itself if it is self-sufficient.
default booleanDetermine whether the given class is reloadable (in this ClassLoader).
default Class<?>Define a custom class (typically a CGLIB proxy class) in this class loader.
isClassReloadabledefault boolean isClassReloadable
(Class<?> clazz)Determine whether the given class is reloadable (in this ClassLoader).
Typically used to check whether the result may be cached (for this ClassLoader) or whether it should be reobtained every time. The default implementation always returns
clazz- the class to check (usually loaded from this ClassLoader)
- whether the class should be expected to appear in a reloaded
version (with a different
Classobject) later on
getOriginalClassLoaderdefault ClassLoader getOriginalClassLoader()Return the original ClassLoader for this SmartClassLoader, or potentially the present loader itself if it is self-sufficient.
The default implementation returns the local ClassLoader reference as-is. In case of a reloadable or other selectively overriding ClassLoader which commonly deals with unaffected classes from a base application class loader, this should get implemented to return the original ClassLoader that the present loader got derived from (e.g. through
This gets specifically used in Spring's AOP framework to determine the class loader for a specific proxy in case the target class has not been defined in the present class loader. In case of a reloadable class loader, we prefer the base application class loader for proxying general classes not defined in the reloadable class loader itself.
publicDefineClassdefault Class<?> publicDefineClass
(String name, byte b, @Nullable ProtectionDomain protectionDomain)Define a custom class (typically a CGLIB proxy class) in this class loader.
This is a public equivalent of the protected
defineClass(String, byte, int, int, ProtectionDomain)method in
ClassLoaderwhich is traditionally invoked via reflection. A concrete implementation in a custom class loader should simply delegate to that protected method in order to make classloader-specific definitions publicly available without "illegal access" warnings on JDK 9+:
return defineClass(name, b, 0, b.length, protectionDomain). Note that the JDK 9+
Lookup#defineClassmethod does not support a custom target class loader for the new definition; it rather always defines the class in the same class loader as the lookup's context class.
name- the name of the class
b- the bytes defining the class
protectionDomain- the protection domain for the class, if any
- the newly created class
LinkageError- in case of a bad class definition
SecurityException- in case of an invalid definition attempt
UnsupportedOperationException- in case of a custom definition attempt not being possible (thrown by the default implementation in this interface)
- See Also: