FULL PRODUCT VERSION :
ava version "1.8.0_112-ea"
ava(TM) SE Runtime Environment (build 1.8.0_112-ea-b04)
ava HotSpot(TM) 64-Bit Server VM (build 25.112-b04, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
The default behavior of URLConnection is to use caching. This can cause file descriptor leaks / locked files when using JarURLConnection.

My suggestion is that the constructor for JarURLConnection be modified to change the default for useCaches to false for JarURLConnection instances.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
https://github.com/markt-asf/memory-leaks/blob/master/src/org/apache/markt/leaks/net/JarUrlConnectionLeak.java

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The temporary JAR file is deleted by the test.
ACTUAL -
The JAR cannot be deleted until the JVM exits.

FAIL: [C:\Users\ADMINI~1\AppData\Local\Temp\testJar6646122445884823355.jar] could not be deleted

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
https://github.com/markt-asf/memory-leaks/blob/master/src/org/apache/markt/leaks/net/JarUrlConnectionLeak.java
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Disable caching before using JarUrlConnection