Depends what are you going to do in your life.

Java and SQL is a good foundation for a developer career. Both
are multiplatform standards, independent of platform (UNIX, Windows).
They a independent of a database engine to a high degree, too.

If you wnat to be a system administrator UNIX skills are usefull.

If you try to be both be carefull not to find a job where you will
fulfill both roles and get payed a usual single salary. Bigger companies
tend to have different positions for those roles. In a smaller
companies, that could be not the case, which might not be bad if you are
paid enough.

DG