The API for TitledBorder is inconsistent with its implementation. The API for the DEFAULT_POSITION static states:

"Use the default vertical orientation for the title text."

However, the actual implementation defaults to a hardcoded value of TOP instead of DEFAULT_POSITION when a position is not specified. Among the side effects of this is that the Nimbus LAF cannot correctly specify a different default position other than TOP. Ideally, the implementation would be brought into conformance with the spec, and the default text position would be DEFAULT_POSITION.