RobotnixAcademy

Unit 07 · lesson

Bridge Checkpoint: Discovery Requires a Runtime That Can Discover

A Java collection can only contain what the program placed there. Runtime discovery is different.

Use supplied or local ROS 2 evidence to inspect one graph inventory. Compare it with a local Java component inventory.

Ask:

  • who produced each list;
  • whether the list is static, configured, or discovered;
  • whether missing entries mean absence, invisibility, or simply different scope;
  • what timestamp/environment belongs to the observation.

A ROS graph snapshot can prove that graph entities were visible at that moment. It does not prove the Java application knows about them.

Likewise, a Java inventory can prove what the application modeled. It does not prove the ROS graph contains matching entities.

Comparison record

Create three rows:

local Java inventory
ROS runtime inventory
physical-device inventory

For each, name the tool or mechanism that would produce trustworthy evidence.

The purpose is not to learn ArrayList again. The purpose is to stop treating every list of component names as the same kind of evidence.