Java Optimization Framework

Question

I'm looking for a java framework, which is suitable for optimization tasks. In best case it's realized with Java 8. I know there are better languages for optimization tasks, but currently I'm restricted to Java.

It should do:

public class OptimizationProblem {

    // Given: Any function, which returns a value for a combination of A and B.
    public int value (A a, B b);
    List<A> as;
    List<B> bs;

    // This function should be part of the framework
    // It should map each A to one B (if both are of same length), so that the value
    // in sum is max (not an easy task, at all).
    Map<A, B> map = findBestCombinations (as, bs, OptimizationProblem::value);

I expect the framework to handle minimization and maximization problems. It does not have to find the "optimal" solution to given problems. If it's not possible to find the solution in an adequate time, it's allowed to return a "good" solution.

Answer 1

Since I'm looking for a Java library for quadratic programming (Solve small quadratic programming problem with inequality constraints in Java or C/C++), I've come across some items. I think this general question about optimization packages for Java will be useful to others, so here are my notes about some items I looked at. These should be understood as relating only to the version of the software at the present time (September 2018). This list is non-exhaustive.

• oj! Algorithms (https://github.com/optimatika/ojAlgo) -- might be able to handle QP; I'm looking at it now.
• Stanford NLP (https://github.com/stanfordnlp/CoreNLP) -- has some functions for general unconstrained optimization, but I don't see anything for QP specifically or constrained problems.
• JOptimizer (http://www.joptimizer.com) -- appears to be able to handle QP with equality and inequality constraints.