Spring PathMatchingResourcePatternResolver fails to resolve resources from JAR located in path with '#' on JDK 11+

Affects: Spring Framework 5.3.1 on JRE 11+

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I have a simple JAR which contains the resource demo/dummy.txt and a class with this code:

ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
Resource[] resources = resolver.getResources("classpath*:**/dummy.txt");
System.out.println("resources = " + Arrays.toString(resources));

If I put this JAR into c:\tmp\demo and run the code, the resource is found. If I put this JAR into c:\tmp\#demo and run the code, no resources are found. Instead, an exception is logged at debug level:

Cannot search for matching files underneath [c:\tmp\#demo\resource-resolver-demo-1.0-SNAPSHOT.jar] because it cannot be converted to a valid 'jar:' URL: no !/ in spec

java.net.MalformedURLException: no !/ in spec
    at java.base/java.net.URL.<init>(URL.java:679)
    at java.base/java.net.URL.<init>(URL.java:541)
    at java.base/java.net.URL.<init>(URL.java:488)
    at org.springframework.core.io.UrlResource.<init>(UrlResource.java:95)
    at org.springframework.core.io.support.PathMatchingResourcePatternResolver.addClassPathManifestEntries(PathMatchingResourcePatternResolver.java:435)
    at org.springframework.core.io.support.PathMatchingResourcePatternResolver.addAllClassLoaderJarRoots(PathMatchingResourcePatternResolver.java:400)
    at org.springframework.core.io.support.PathMatchingResourcePatternResolver.doFindAllClassPathResources(PathMatchingResourcePatternResolver.java:346)
    at org.springframework.core.io.support.PathMatchingResourcePatternResolver.findAllClassPathResources(PathMatchingResourcePatternResolver.java:321)
    at org.springframework.core.io.support.PathMatchingResourcePatternResolver.getResources(PathMatchingResourcePatternResolver.java:288)
    at org.springframework.core.io.support.PathMatchingResourcePatternResolver.findPathMatchingResources(PathMatchingResourcePatternResolver.java:494)
    at org.springframework.core.io.support.PathMatchingResourcePatternResolver.getResources(PathMatchingResourcePatternResolver.java:284)
    at demo.ResourceResolverDemo.main(ResourceResolverDemo.java:13)
Caused by: java.lang.NullPointerException: no !/ in spec
    at java.base/sun.net.www.protocol.jar.Handler.parseAbsoluteSpec(Handler.java:181)
    at java.base/sun.net.www.protocol.jar.Handler.parseURL(Handler.java:163)
    at java.base/java.net.URL.<init>(URL.java:674)
    ... 11 more

This is only reproducible with JRE 11 and newer. Both cases work as expected if I run them with JRE 8.

See also this demo project: https://github.com/rweisleder/resource-resolver-demo

Comment From: jhoeller

@rweisleder, I've just committed a revision that encodes the hash symbol in addClassPathManifestEntries, verified with some local tests. Please give the latest 5.3.2 snapshot (https://repo.spring.io/snapshot/org/springframework/spring-framework-bom/) a try and let me know whether this works in your scenario as well... I'll backport it to 5.2.12 and 5.1.20 then (where we aim for JDK 11 compatibility as well).

Comment From: rweisleder

It worked for me with spring-core-5.3.2-20201118.144452-29.jar Thanks for the quick response and fix!