FULL PRODUCT VERSION :
java version "9-ea"
Java(TM) SE Runtime Environment (build 9-ea+155)
Java HotSpot(TM) 64-Bit Server VM (build 9-ea+155, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Darwin aw-rmbp.home 14.5.0 Darwin Kernel Version 14.5.0: Sun Sep 25 22:07:15 PDT 2016; root:xnu-2782.50.9~1/RELEASE_X86_64 x86_64

A DESCRIPTION OF THE PROBLEM :
I am a developer on Spring Boot where we use the java.protocol.handler.pkgs system property to install a custom URLStreamHandler for jar URLs. The custom handler enables Spring Boot's support for nested jars with a single, executable "fat" jar. This works fine on Java 6, 7, and 8

Running on Java 9, our custom URLStreamHandler is no longer used for URLs with which a URLClassLoader has been configured. This breaks our executable jar support. I believe this is due to this change in OpenJDK: http://hg.openjdk.java.net/jdk9/jdk9/jdk/diff/c49b0409a802/src/java.base/share/classes/jdk/internal/loader/URLClassPath.java

REGRESSION. Last worked in version 8u121

ADDITIONAL REGRESSION INFORMATION:
java version "1.8.0_121"
Java(TM) SE Runtime Environment (build 1.8.0_121-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Please see https://github.com/wilkinsona/jar-handler-regression

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The output should be:

URLs handled by custom handler: 1
ACTUAL -
The output is:

URLs handled by custom handler: 0

REPRODUCIBILITY :
This bug can be reproduced always.

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Please see https://github.com/wilkinsona/jar-handler-regression
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