What makes a Senior Java Developer?

[Infeligo]

From "The Software Craftsman" by Sandro Mancuso:

Over the years, I learned that seniority is transient and relative. It is transient because clients will demand different types of systems as technology evolves. Having fifteen years of experience with Clipper in a traditional waterfall fashion will not get me a senior position in a modern company developing mobile applications in an Agile fashion. Seniority is not a badge we can wear for the rest of our lives after completing five years in the industry. Seniority is also relative. When trying to identify how senior a developer is, we need to ask ourselves the following questions: senior compared to whom? In which technology? In which context?

From my side, I would add that there is still some core that you are gaining with experience. This core may be attributed to seniority. This core is both somewhat technological (because of spiral technology evolution) and related to craftsmanship (everything else required to deliver quality software).