XALANJ-2664: Determine the parent ClassLoader for ByteArrayClassLoader

[jamesnetherton]

No description provided.

[jkesselm]

The change looks harmless, but an explanation/justification would still be good practice, eg mention what breaks without the super(parent).

[jamesnetherton]

@jkesselm there's an overview here:

https://issues.apache.org/jira/browse/XALANJ-2664

My use case is for XSLT with Apache Camel Quarkus where we support running applications natively on GraalVM. We have to do translet compilation at build time since it can't be done dynamically at runtime with GraalVM.

Due to how Quarkus organises its ClassLoaders for the build time augmentation phase, relying on the system ClassLoader is not guaranteed to work.

Hence using get ObjectFactory to figure out the parent ClassLoader. Which seems to be consistent with how things are done elsewhere, like in TransletClassLoader:

xalan-java/xalan/src/main/java/org/apache/xalan/xsltc/trax/TemplatesImpl.java

Lines 283 to 288 in c8ddaad

	TransletClassLoader loader = (TransletClassLoader)
	AccessController.doPrivileged(new PrivilegedAction() {
	public Object run() {
	return new TransletClassLoader(ObjectFactory.findClassLoader());
	}
	});

xalan-java/xalan/src/main/java/org/apache/xalan/xsltc/trax/TemplatesImpl.java

Lines 119 to 130 in c8ddaad

	static final class TransletClassLoader extends ClassLoader {
	TransletClassLoader(ClassLoader parent) {
	super(parent);
	}
	/**
	* Access to final protected superclass member from outer class.
	*/
	Class defineClass(final byte[] b) {
	return defineClass(null, b, 0, b.length);
	}
	}