We used LaguerreSolver.solveAll() in version 2.1, but we never upgraded to 2.2. As such, we didn't notice that it was deprecated in that release.
Now that 3.0 is out, we want to upgrade, but that method has been completely removed.
Interestingly, the logic is still there in the library in an inner class: org.apache.commons.math3.analysis.solvers.LaguerreSolver.ComplexSolver. Unfortunately for us, though, ComplexSolver is now private. So, for us as users, we've lost access to a useful algorithm that is still in the library.
Please re-enable access to this useful algorithm that proves complex roots of polynomial formulae. The simplest approach might be to make LaguerreSolver.ComplexSolver public, but perhaps another approach would be considered better design.