'$' characters in class names are converted to '.' in joinpoint's 'toString' method

[kriegaex]

I just had a case in which my execution pointcut explicitly targeted a JDK proxy. When logging the joinpoint during advice execution, the $ had been replaced by .. During LTW, the class name was still displayed correctly.

[AppClassLoader@18b4aac2] weaveinfo at Type 'jdk.proxy2.$Proxy92' (no debug info available)::0 Join point 'method-execution(long jdk.proxy2.$Proxy92.getCount())' in Type 'jdk.proxy2.$Proxy92' (no debug info available) advised by before advice from 'uk.vaent.aspect.MyAspect' (MyAspect.java) [with runtime test]
	see also: uk\vaent\aspect\MyAspect.java::0
execution(long jdk.proxy2..Proxy92.getCount())

See? execution(long jdk.proxy2.$Proxy92.getCount()) during weaving, but execution(long jdk.proxy2..Proxy92.getCount()) during advice execution.

The root cause seems to be here:

aspectj/runtime/src/main/java/org/aspectj/runtime/reflect/StringMaker.java

Lines 90 to 101 in 5813dd5

	String makeTypeName(Class<?> type, String typeName, boolean shortName) {
	if (type == null) return "ANONYMOUS";
	if (type.isArray()) {
	Class<?> componentType = type.getComponentType();
	return makeTypeName(componentType, componentType.getName(), shortName) + "[]";
	}
	if (shortName) {
	return stripPackageName(typeName).replace('$', '.');
	} else {
	return typeName.replace('$', '.');
	}
	}

What exactly is the reason for the .replace('$', '.')? This behaviour traces back to the initial version 23 years ago.

[kriegaex]

@aclement, can you maybe explain that? I cannot ask Wes Isberg. It is more or less cosmetic, but ugly anyhow.

Thinking aloud: Does the string maker maybe assume that a $ in any class name must always be a separator for an inner class name like in Outer$Inner, e.g. org.aspectj.runtime.reflect.JoinPointImpl$StaticPartImpl? But a dynamic proxy class name does in fact start with a $ character.

[wti]

Does the string maker maybe assume that a $ in any class name must always be a separator for an inner class name like in Outer$Inner

Yes. per logic (from JDK's Symbol) back-convert as a nested-class delimiter. It was a bug not to consider a leading dot for dynamic proxy names (1.3 in 2000), but I'm not sure what would have been the correct thing to do since dynamic proxies have no source name. You could probably safely special-case the leading character. I believe for bytecode only ., ;, [, and / are disallowed b/c used internally. For source, it's legal to use $ inside a type name in java source :)

[kriegaex]

It was a bug not to consider a leading dot for dynamic proxy names

@wti, did you mean to say, "to consider a leading dollar sign for dynamic proxy names"?