Package org.apache.flink.util

Class FlinkUserCodeClassLoaders.SafetyNetWrapperClassLoader

java.lang.Object

java.lang.ClassLoader

java.security.SecureClassLoader

java.net.URLClassLoader

org.apache.flink.util.MutableURLClassLoader

org.apache.flink.util.FlinkUserCodeClassLoaders.SafetyNetWrapperClassLoader

All Implemented Interfaces:

Closeable, AutoCloseable

Enclosing class:

FlinkUserCodeClassLoaders

@Internal
public static class FlinkUserCodeClassLoaders.SafetyNetWrapperClassLoader
extends MutableURLClassLoader

Ensures that holding a reference on the context class loader outliving the scope of user code does not prevent the user classloader to be garbage collected (FLINK-16245).

This classloader delegates to the actual user classloader. Upon close(), the delegate is nulled and can be garbage collected. Additional class resolution will be resolved solely through the bootstrap classloader and most likely result in ClassNotFound exceptions.

Field Summary

Fields

Modifier and Type	Field	Description
protected FlinkUserCodeClassLoader	inner

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SafetyNetWrapperClassLoader(FlinkUserCodeClassLoader inner, ClassLoader parent)

Method Summary

Modifier and Type	Method	Description
void	addURL(URL url)
void	close()
MutableURLClassLoader	copy()	Copy the classloader for each job and these jobs can add their jar files to the classloader independently.
URL	getResource(String name)
Enumeration<URL>	getResources(String name)
URL[]	getURLs()
Class<?>	loadClass(String name)
protected Class<?>	loadClass(String name, boolean resolve)

Methods inherited from class java.net.URLClassLoader

definePackage, findClass, findResource, findResources, getPermissions, getResourceAsStream, 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, toString, wait, wait, wait

Field Detail

inner

protected volatile FlinkUserCodeClassLoader inner

Constructor Detail

SafetyNetWrapperClassLoader

protected SafetyNetWrapperClassLoader(FlinkUserCodeClassLoader inner,
                                      ClassLoader parent)

Method Detail

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class URLClassLoader

loadClass

public Class<?> loadClass(String name)
                   throws ClassNotFoundException

Overrides:

loadClass in class ClassLoader

Throws:

ClassNotFoundException

loadClass

protected Class<?> loadClass(String name,
                             boolean resolve)
                      throws ClassNotFoundException

Overrides:

loadClass in class ClassLoader

Throws:

ClassNotFoundException

addURL

public void addURL(URL url)

Overrides:

addURL in class MutableURLClassLoader

copy

public MutableURLClassLoader copy()

Description copied from class: MutableURLClassLoader

Copy the classloader for each job and these jobs can add their jar files to the classloader independently.

Specified by:

copy in class MutableURLClassLoader

Returns:

the copied classloader

getResource

public URL getResource(String name)

Overrides:

getResource in class ClassLoader

getResources

public Enumeration<URL> getResources(String name)
                              throws IOException

Overrides:

getResources in class ClassLoader

Throws:

IOException

getURLs

public URL[] getURLs()

Overrides:

getURLs in class URLClassLoader