testTagOrNull

The tag testTag set on this component, or null where it carries none: a component the modifier was never applied to, and one that is no JComponent and so holds no client properties at all.

A test harness resolves a tagged component through this. What the library publishes is the read; the slot the tag sits in stays its own.

Marked InternalSwingUiApi; it may change or be removed without notice in any release.