Why Java Classloader does not release jars

Question

I need to load classes from jars, to do it I'm using:

cls = Class.forName(className, false, classLoader);

At the end, I want to delete these jars, but it seems that this is not possible because ClassLoader does not release the jars. So I used:

classLoader.release();

System.gc();

But unfortunately this does not solve the problem...

@khouloud What's your use case? Why are you trying to release your JARs from memory? — entpnerd, Nov 15 '19 at 06:17
@entpnerd I'm working with a custom classloader extending from ClassLoader. I'm trying to release jars, so I can delete these jars. — khouloud, Nov 15 '19 at 09:06
Ok, so why are you writing a custom class loader that can release JARs? — entpnerd, Nov 15 '19 at 09:08
FYI I'm trying to drilldown on the business case to try to determine whether some workaround can be done. — entpnerd, Nov 15 '19 at 09:51

score 1 · Answer 1 · answered Nov 14 '19 at 10:42

According to the JLS, classes (and therefore JAR-files) cannot be unloaded explicitly.

It might be possible to achieve something similar with some trickery as described here, but it depends on the actual implementation of the JVM and is therefore nothing you should build on.

Why Java Classloader does not release jars

1 Answers1