Assuming that you meant to state 'Class Diagram' instead of 'Project Hierarchy', I've used the following Eclipse plug-ins to generate Class Diagrams at various points in my professional career:
EclipseUML from Omondo. Only commercial versions appear to be available right now. The class diagram in your question, is most likely generated by this plugin.
Obligatory links
The listed tools will not generate class diagrams from source code, or atleast when I used them quite a few years back. You can use them to handcraft class diagrams though.
UMLet. I used this several years back. Appears to be in use, going by the comments in the Eclipse marketplace.
Violet. This supports creation of other types of UML diagrams in addition to class diagrams.
Except for ObjectAid and a few other mentions, most of the Eclipse plug-ins mentioned in the listed questions may no longer be available, or would work only against older versions of Eclipse.
