When adding Groovy Files from the file system to the GroovyClassLoader's classpath grabbed from a default java properties file ("/" instead of "\"))
Then the addClasspath() method uses a simple URL instead of the File URL
This is due to a simple mistake in this mentioned method:
The URI_PATTERN which should match "URIs but not Windows filenames" doesn't work as expected.
It matches i.e. C:/xxx/file.ext
This is related to using forward instead of backslashes - which souldn't matter.
This was i.e. NOT the case for Groovy 2.1.3