Inspect --module-path value at runtime

Question

Is there any way to get list of directories which are included in module-path with use of -p or --module-path arguments at runtime similar to how I whold get all classpath directories using System.getProperty("java.class.path")?

Fabricate

Why do you need the modulepath? What use case do you have? – Walther

@Walther Just for debug purposes – Fabricate

The system property is jdk.module.path, documented in System.getProperties(). For completeness, you may want to look at the value of jdk.module.upgrade.path, also documented in System.getProperties(). – Sakti

@AlanBateman But why I don't have such systems properties even when --module-path was actually used? I am using java.runtime.version=9+181 – Fabricate

Answer 1

From Javadoc of System.getProperties:

In addition to the standard system properties,
the system properties may include the following keys:

Key                      Description of Associated Value
jdk.module.path          The application module path
jdk.module.upgrade.path  The upgrade module path
jdk.module.main          The module name of the initial/main module
jdk.module.main.class    The main class name of the initial module

So you should use System.getProperty("jdk.module.path")

Walther

A better way would be as suggested by Alan – Paniagua