Remove binary array name handling in `ClassUtils.forName()`

[sbrannen]

Overview

For a bit of background, we seem to have flipped back and forth between using Class.forName() and ClassLoader.loadClass() over the years, but in Spring Framework 5.1.1 we switched from ClassLoader.loadClass() to Class.forName() in ClassUtils.forName() (see #21867).

Thanks to a discovery made by @sormuras (see junit-team/junit-framework#4250), I have learned that Class.forName() has built-in support for binary array names; whereas, ClassLoader.loadClass() does not.

In light of that, we should be able to remove the following custom support for binary array names:

spring-framework/spring-core/src/main/java/org/springframework/util/ClassUtils.java

Lines 300 to 312 in eda7af7

	// "[Ljava.lang.String;" style arrays
	if (name.startsWith(NON_PRIMITIVE_ARRAY_PREFIX) && name.endsWith(";")) {
	String elementName = name.substring(NON_PRIMITIVE_ARRAY_PREFIX.length(), name.length() - 1);
	Class<?> elementClass = forName(elementName, classLoader);
	return elementClass.arrayType();
	}
	// "[[I" or "[[Ljava.lang.String;" style arrays
	if (name.startsWith(INTERNAL_ARRAY_PREFIX)) {
	String elementName = name.substring(INTERNAL_ARRAY_PREFIX.length());
	Class<?> elementClass = forName(elementName, classLoader);
	return elementClass.arrayType();
	}

I removed that and tested locally in Eclipse and with a full Gradle build, and all tests pass.

Related Issues

• Remove custom array handling already covered by Class.forName() junit-team/junit-framework#4250
• ClassUtils could use long form of Class.forName [SPR-17333] #21867