[caoilte]

Do the Coursera courses and demonstrate an interest. When we hire we look for developers with 2-3 languages under their belt. Only one has to be professional for a jnr/mid candidate. Most other Scala shops I know of work the same way.

Even this low bar eliminates 90% of candidates so it won't take much for you to shine at this level.

If you're snr then you might find yourself actually having to introduce Scala at a Java shop. Run dojos, lunchtime lightning/brown bag talks and lever it in as a testing framework or throwaway prototype. If that doesn't work, start questioning what you did to deserve being called snr.