@Razi Kheir FromResource() will load from the classpath and not from a file on disk

I see, so resource comes first but file system is just before last? Why is it not detecting my filesystem override unless its the first in line?

There shouldn't be a special order apart from the chain that you specify.

I mean if I put the filesystem environment as the first override everything works prefectly the lenses read the variables etc. If I put it under jvm flags, suddenly it throws lens exception

Yes - that the expected behaviour.

Ill do that later today 🙂 thanks

Here's my experiment, which works ok:

fun main() {
    /**
     * Given: foo.propertie
     * 
     * foo=bar
     */
    val key = EnvironmentKey.required("foo")

    val file = Environment.from(File("path/foo.properties"))

    val comp = Environment.from("BAR" to "foo") overrides file

    println(key(comp))
}