ADDITIONAL SYSTEM INFORMATION :
OS assumed unimportant but was macOS Monterey 12.6.1
Openjdk version "11.0.17" 2022-10-18 LTS

A DESCRIPTION OF THE PROBLEM :
The behaviour of getResource differs between J8 and J11 (most likely later JREs) when the classpath contains a multi-release jar.

With J8 or with J11 and no multi release jar.

Calling ClassLoader.getResource("") will return null as would be expected.

With J11 and a multi release jar on the classpath

Calling ClassLoader.getResource("") will return a non-null but invalid resource, equivalent to the multi-release folder for the version of Java running. E.g. e.g. some.jar!/META-INF/versions/11/

REGRESSION : Last worked in version 8u351

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Using a multi release jar on java 11 make a call to a Classloader instance to the method getResource with the empty string

classLoader.getResource("");

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
If the behaviour matched Java 8, or without a multi-release jar, then we would expect null should be returned.
ACTUAL -
On Java 11with a mutli-release jar an invalid resource will be returned.

This resource matches the directory for the multi-release jar classes that match the Java version

e.g. some.jar!/META-INF/versions/11/

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See attached zip file.
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CUSTOMER SUBMITTED WORKAROUND :
Refrain from fetching empty strings.

FREQUENCY : always