diff --git a/core/src/main/java/hudson/os/PosixAPI.java b/core/src/main/java/hudson/os/PosixAPI.java
index 2e69069c1c2e4a94e7dfbb782be4e12d9112cbc4..f54f29331e8a1f3c7dfc4169e8c9089dac13f1b0 100644
--- a/core/src/main/java/hudson/os/PosixAPI.java
+++ b/core/src/main/java/hudson/os/PosixAPI.java
@@ -22,6 +22,7 @@ public class PosixAPI {
     /**
      * Load the JNR implementation of the POSIX APIs for the current platform.
      * Runtime exceptions will be of type {@link PosixException}.
+     * {@link IllegalStateException} will be thrown for methods not implemented on this platform.
      * @return some implementation (even on Windows or unsupported Unix)
      * @since 1.518
      */