org.jboss.weld.util.bytecode

Class ClassFileUtils

java.lang.Object

org.jboss.weld.util.bytecode.ClassFileUtils

public class ClassFileUtils
extends Object

Utility class for loading a ClassFile into a classloader. Allows to use either old approach directly via CL methods, or delegation to integrator through ProxyServices. Also contains logic needed to crack open CL methods should that approach be used - this is invoked from WeldStartup. In oder to support JDK 9+, this class now uses Unsafe as we need to be able to define classes with different ProtectionDomain In JDK 12+, even Unsafe fails (no "override" field) hence we fallback to setAccessible() but in this case integrators should already go through new SPI hence avoiding this problem.

Author:

Stuart Douglas, Matej Novotny

Method Summary

Modifier and Type	Method and Description
static void	makeClassLoaderMethodsAccessible() This method cracks open ClassLoader#defineClass() methods using Unsafe.
static Class<?>	toClass(org.jboss.classfilewriter.ClassFile ct, Class<?> originalClass, org.jboss.weld.serialization.spi.ProxyServices proxyServices, ProtectionDomain domain) Delegates proxy creation via ProxyServices to the integrator.
static Class<?>	toClass(org.jboss.classfilewriter.ClassFile ct, ClassLoader loader, ProtectionDomain domain) Converts the class to a java.lang.Class object.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

makeClassLoaderMethodsAccessible

public static void makeClassLoaderMethodsAccessible()

This method cracks open ClassLoader#defineClass() methods using Unsafe. It is invoked during WeldStartup#startContainer() and only in case the integrator does not fully implement ProxyServices. Method first attempts to use Unsafe and if that fails then reverts to setAccessible

toClass

public static Class<?> toClass(org.jboss.classfilewriter.ClassFile ct,
                               ClassLoader loader,
                               ProtectionDomain domain)

Converts the class to a java.lang.Class object. Once this method is called, further modifications are not allowed any more.

The class file represented by the given CtClass is loaded by the given class loader to construct a java.lang.Class object. Since a private method on the class loader is invoked through the reflection API, the caller must have permissions to do that.

An easy way to obtain ProtectionDomain object is to call getProtectionDomain() in java.lang.Class. It returns the domain that the class belongs to.

This method is provided for convenience. If you need more complex functionality, you should write your own class loader.

Parameters:

loader - the class loader used to load this class. For example, the loader returned by getClassLoader() can be used for this parameter.

domain - the protection domain for the class. If it is null, the default domain created by java.lang.ClassLoader is

toClass

public static Class<?> toClass(org.jboss.classfilewriter.ClassFile ct,
                               Class<?> originalClass,
                               org.jboss.weld.serialization.spi.ProxyServices proxyServices,
                               ProtectionDomain domain)

Delegates proxy creation via ProxyServices to the integrator.