I once interviewed (and got the job) for a java dev position with a mostly C/C++ background.

One of the issues to solve during the tech interview was fixing a bug in a fairly involved web app with a java backend. Long story short, it boiled down to "==" being used to compare two strings instead of ".equals" somewhere deep in their class hierarchy.

I found it and fixed it, even though I was not familiar with the reference vs value equality difference in java. General debugging skills acquired over years should allow you to track down exactly where things go more wrong than expected, and then help you reason about why it goes wrong.