I don't know where you read that, but it's not in the J3D documentation,
"Only one path exists from the root of a tree to each of the leaves; therefore, there is only one path from the root of a scene graph to each leaf node. The path from the root of a scene graph to a specific leaf node is the leaf node’s scene graph path. Since a scene graph path leads to exactly one leaf, there is one scene graph path for each leaf in the scene graph."
The Java 3D Tutorial, Chapter 1. Getting Started, page 1-3, paragraph 4.
