diff --git a/README.md b/README.md
index a355d23f..897d214c 100644
--- a/README.md
+++ b/README.md
@@ -81,6 +81,29 @@ Further examples can be found directly within this repository in the [Examples P
 * How to run a [stochastic simulation](https://github.com/draeger-lab/SBSCL/blob/master/src/main/java/fern/Start.java)
 
 
+## Using OptSolvX (LP) in SBSCL
+
+### Run the OptSolvX demo
+
+* In your IDE, run: `org.simulator.optsolvx.OptSolvXDemo`.
+* The demo builds a tiny LP and solves it via OptSolvX (CommonsMath backend for now).
+* Make sure the OptSolvX **jdk8** artifact is on the classpath (declared in SBSCL’s `pom.xml`).
+
+### Enable debug logs
+
+Create the adapter with `debug = true`:
+
+```java
+LPSolverAdapter solver =
+    new OptSolvXSolverAdapter(new CommonsMathSolver(), true);
+```
+
+### (Preview) SBML/FBC → LP
+
+An experimental entry point is available at `org.simulator.optsolvx.FbaToOptSolvX`.
+
+
+
 ### Comparison to Similar Libraries
 
 To compare SBSCL to other simulation engines and to benchmark its predictions and results, a separate project, [SBSCL simulator comparison](https://github.com/matthiaskoenig/sbscl-simulator-comparison), is available.
diff --git a/pom.xml b/pom.xml
index e162e1e8..de26c1f9 100644
--- a/pom.xml
+++ b/pom.xml
@@ -471,6 +471,14 @@
         </exclusion>
       </exclusions>
     </dependency>
+
+    <!-- OptSolvX -->
+    <dependency>
+      <groupId>org.optsolvx</groupId>
+      <artifactId>optsolvx</artifactId>
+      <version>0.1.0-SNAPSHOT</version>
+      <classifier>jdk8</classifier>
+    </dependency>
   </dependencies>
 
 
diff --git a/src/main/java/org/simulator/optsolvx/FbaToOptSolvX.java b/src/main/java/org/simulator/optsolvx/FbaToOptSolvX.java
new file mode 100644
index 00000000..300ef4bb
--- /dev/null
+++ b/src/main/java/org/simulator/optsolvx/FbaToOptSolvX.java
@@ -0,0 +1,194 @@
+package org.simulator.optsolvx;
+
+import org.optsolvx.model.AbstractLPModel;
+import org.optsolvx.model.Constraint;
+import org.optsolvx.model.OptimizationDirection;
+import org.sbml.jsbml.*;
+import org.sbml.jsbml.ext.fbc.*;
+
+import java.text.MessageFormat;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.logging.Logger;
+
+/**
+ * SBML/FBC -> OptSolvX bridge (minimal functional version).
+ * Maps reactions to variables (with bounds), builds S·v=0 constraints, and sets the active objective.
+ * NOTE: This intentionally ignores InitialAssignments and StoichiometryMath for now (TODO).
+ */
+public final class FbaToOptSolvX {
+    private static final Logger LOGGER = Logger.getLogger(FbaToOptSolvX.class.getName());
+
+    private FbaToOptSolvX() { /* no instances */ }
+
+    /** Build an OptSolvX LP model from SBML/FBC (v1 or v2). */
+    public static AbstractLPModel fromSBML(SBMLDocument doc) {
+        if (doc == null || !doc.isSetModel()) {
+            throw new IllegalArgumentException("SBMLDocument must contain a Model.");
+        }
+        final Model m = doc.getModel();
+
+        // Prepare LP model
+        final AbstractLPModel lp = new AbstractLPModel();
+
+        // Resolve FBC namespaces for level/version
+        final int level = doc.getLevel();
+        final int version = doc.getVersion();
+        final String fbcNSv1 = FBCConstants.getNamespaceURI(level, version, 1);
+        final String fbcNSv2 = FBCConstants.getNamespaceURI(level, version, 2);
+
+        // --- 1) Variables (reactions) with bounds ---------------------------------------------
+        // Default bounds if FBC has no values: 0 .. +inf (conventional for FBA)
+        final Map<String, Double> lb = new LinkedHashMap<>();
+        final Map<String, Double> ub = new LinkedHashMap<>();
+
+        for (Reaction r : m.getListOfReactions()) {
+            String rid = r.getId();
+            double lower = 0.0d;
+            double upper = Double.POSITIVE_INFINITY;
+
+            // FBC v2: bounds via FBCReactionPlugin lower/upper "Parameter" instances
+            if (r.isSetPlugin(fbcNSv2)) {
+                FBCReactionPlugin rp = (FBCReactionPlugin) r.getPlugin(fbcNSv2);
+                Parameter lpi = rp.getLowerFluxBoundInstance();
+                Parameter upi = rp.getUpperFluxBoundInstance();
+                if (lpi != null) lower = valueOf(lpi);
+                if (upi != null) upper = valueOf(upi);
+            }
+            // Store preliminary bounds; FBC v1 may override below via FluxBounds list
+            lb.put(rid, lower);
+            ub.put(rid, upper);
+        }
+
+        // FBC v1: FluxBounds at model level (override)
+        FBCModelPlugin mpV1 = (FBCModelPlugin) m.getPlugin(fbcNSv1);
+        if (mpV1 != null && mpV1.isSetListOfFluxBounds()) {
+            for (FluxBound fb : mpV1.getListOfFluxBounds()) {
+                String rid = fb.getReaction();
+                if (rid == null) continue;
+                switch (fb.getOperation()) { // Java 8 compatible switch
+                    case GREATER_EQUAL:
+                        lb.put(rid, fb.getValue());
+                        break;
+                    case LESS_EQUAL:
+                        ub.put(rid, fb.getValue());
+                        break;
+                    case EQUAL:
+                        lb.put(rid, fb.getValue());
+                        ub.put(rid, fb.getValue());
+                        break;
+                    default:
+                        LOGGER.warning("FBC v1: Unsupported FluxBound operation on " + rid);
+                }
+            }
+        }
+
+        // Add variables to LP
+        for (Reaction r : m.getListOfReactions()) {
+            String rid = r.getId();
+            double lower = nvl(lb.get(rid), 0.0d);
+            double upper = nvl(ub.get(rid), Double.POSITIVE_INFINITY);
+            lp.addVariable(rid, lower, upper);
+        }
+
+        // --- 2) Mass-balance constraints S·v = 0 (ignore boundary species) ---------------------
+        for (Species s : m.getListOfSpecies()) {
+            boolean isBoundary = s.isSetBoundaryCondition() && s.getBoundaryCondition();
+            if (isBoundary) continue;
+
+            Map<String, Double> coeffs = new LinkedHashMap<>();
+            // For each reaction, accumulate stoichiometry of species s
+            for (Reaction r : m.getListOfReactions()) {
+                double sum = 0.0d;
+                // Reactants contribute negative stoichiometry
+                for (SpeciesReference sr : r.getListOfReactants()) {
+                    if (s.getId().equals(sr.getSpecies())) {
+                        sum += -stoich(sr);
+                    }
+                }
+                // Products contribute positive stoichiometry
+                for (SpeciesReference sr : r.getListOfProducts()) {
+                    if (s.getId().equals(sr.getSpecies())) {
+                        sum += +stoich(sr);
+                    }
+                }
+                if (sum != 0.0d) {
+                    coeffs.put(r.getId(), sum);
+                }
+            }
+            if (!coeffs.isEmpty()) {
+                lp.addConstraint("mb_" + s.getId(), coeffs, Constraint.Relation.EQ, 0.0d);
+            } else {
+                // Optional: many species simply don't appear; keep quiet to avoid noisy logs
+            }
+        }
+
+        // --- 3) Objective (active FBC objective) -----------------------------------------------
+        Map<String, Double> obj = new LinkedHashMap<>();
+        OptimizationDirection dir = OptimizationDirection.MAXIMIZE; // sensible default
+
+        // Prefer FBC v2 at model level; fall back to v1
+        FBCModelPlugin mpV2 = (FBCModelPlugin) m.getPlugin(fbcNSv2);
+        FBCModelPlugin mp = (mpV2 != null) ? mpV2 : mpV1;
+
+        if (mp != null && mp.isSetActiveObjective()) {
+            Objective o = mp.getActiveObjectiveInstance();
+            if (o != null) {
+                // Direction
+                Objective.Type t = o.getType();
+                if (t == Objective.Type.MINIMIZE) {
+                    dir = OptimizationDirection.MINIMIZE;
+                } else if (t == Objective.Type.MAXIMIZE) {
+                    dir = OptimizationDirection.MAXIMIZE;
+                }
+                // Coefficients
+                for (FluxObjective fo : o.getListOfFluxObjectives()) {
+                    String rid = fo.getReaction();
+                    if (rid != null) obj.put(rid, fo.getCoefficient());
+                }
+            } else {
+                LOGGER.warning("No active FBC Objective instance set; using empty objective.");
+            }
+        } else {
+            LOGGER.warning("FBC Objective not set; using empty objective (objective=0).");
+        }
+
+        if (!obj.isEmpty()) {
+            lp.setObjective(obj, dir);
+        } else {
+            // Keep objective empty → objective value will be 0.0; direction still recorded if needed
+            lp.setObjective(new LinkedHashMap<String, Double>(), dir);
+        }
+
+        // --- 4) Finalize & Log -----------------------------------------------------------------
+        lp.build();
+        LOGGER.info(MessageFormat.format(
+                "FbaToOptSolvX: built LP (vars={0}, cons={1}, objectiveVars={2}, dir={3})",
+                lp.getVariables().size(),
+                lp.getConstraints().size(),
+                obj.size(),
+                dir
+        ));
+        return lp;
+    }
+
+    // --- Helpers -----------------------------------------------------------------------------
+
+    /** Get numeric value from a Parameter (defaults to 0.0 if unset). */
+    private static double valueOf(Parameter p) {
+        if (p == null) return 0.0d;
+        // Prefer explicit value; ignoring units & possible initial assignments for now (TODO)
+        return p.isSetValue() ? p.getValue() : 0.0d;
+    }
+
+    /** Null-safe value with default. */
+    private static double nvl(Double v, double def) {
+        return (v != null) ? v.doubleValue() : def;
+    }
+
+    /** Basic stoichiometry extraction (ignores StoichiometryMath & InitialAssignments for now). */
+    private static double stoich(SpeciesReference sr) {
+        if (sr == null) return 0.0d;
+        return sr.isSetStoichiometry() ? sr.getStoichiometry() : 1.0d;
+    }
+}
diff --git a/src/main/java/org/simulator/optsolvx/OptSolvXDemo.java b/src/main/java/org/simulator/optsolvx/OptSolvXDemo.java
new file mode 100644
index 00000000..f5ed8676
--- /dev/null
+++ b/src/main/java/org/simulator/optsolvx/OptSolvXDemo.java
@@ -0,0 +1,50 @@
+package org.simulator.optsolvx;
+
+import org.optsolvx.model.AbstractLPModel;
+import org.optsolvx.model.Constraint;
+import org.optsolvx.model.OptimizationDirection;
+import org.optsolvx.solver.CommonsMathSolver;
+import org.optsolvx.solver.LPSolution;
+import org.optsolvx.solver.LPSolverAdapter;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class OptSolvXDemo {
+    public static void main(String[] args) {
+        // Build a tiny LP: maximize x + y
+        AbstractLPModel model = new AbstractLPModel();
+        model.addVariable("x", 0.0d, Double.POSITIVE_INFINITY);
+        model.addVariable("y", 0.0d, Double.POSITIVE_INFINITY);
+
+        // Objective: max x + y  (Java 8 style map)
+        Map<String, Double> objective = new HashMap<>();
+        objective.put("x", 1.0d);
+        objective.put("y", 1.0d);
+        model.setObjective(objective, OptimizationDirection.MAXIMIZE);
+
+        // Constraints (Java 8 style maps)
+        Map<String, Double> c1 = new HashMap<>();
+        c1.put("x", 1.0d);
+        c1.put("y", 2.0d);
+        model.addConstraint("c1", c1, Constraint.Relation.LEQ, 4.0d);
+
+        Map<String, Double> c2 = new HashMap<>();
+        c2.put("x", 1.0d);
+        model.addConstraint("c2", c2, Constraint.Relation.LEQ, 3.0d);
+
+        // Finalize model
+        model.build();
+
+        // Solve via adapter, using CommonsMath as backend
+        LPSolverAdapter backend = new CommonsMathSolver();
+        LPSolverAdapter solver  = new OptSolvXSolverAdapter(backend, /*debug=*/true);
+
+        LPSolution sol = solver.solve(model);
+
+        // Print result (expected optimum: x=3.0, y=0.5, objective=3.5)
+        System.out.println("Variables: " + sol.getVariableValues());
+        System.out.println("Objective: " + sol.getObjectiveValue());
+        System.out.println("Feasible:  " + sol.isFeasible());
+    }
+}
diff --git a/src/main/java/org/simulator/optsolvx/OptSolvXSolverAdapter.java b/src/main/java/org/simulator/optsolvx/OptSolvXSolverAdapter.java
new file mode 100644
index 00000000..b423f51d
--- /dev/null
+++ b/src/main/java/org/simulator/optsolvx/OptSolvXSolverAdapter.java
@@ -0,0 +1,66 @@
+package org.simulator.optsolvx;
+
+import org.optsolvx.model.AbstractLPModel;
+import org.optsolvx.solver.LPSolution;
+import org.optsolvx.solver.LPSolverAdapter;
+
+import java.util.Objects;
+import java.text.MessageFormat;
+import java.util.logging.Logger;
+
+public final class OptSolvXSolverAdapter implements LPSolverAdapter {
+    private static final Logger LOGGER =
+            Logger.getLogger(OptSolvXSolverAdapter.class.getName());
+
+    private final LPSolverAdapter backend;
+    private final boolean debug;
+
+    /**
+     * @param backend concrete OptSolvX solver (e.g. CommonsMathSolver)
+     * @param debug enable verbose logging
+     */
+    public OptSolvXSolverAdapter(LPSolverAdapter backend, boolean debug) {
+        this.backend = Objects.requireNonNull(backend, "backend must not be null");
+        this.debug = debug;
+    }
+
+    /** Convenience: debug disabled by default. */
+    public OptSolvXSolverAdapter(LPSolverAdapter backend) {
+        this(backend, false);
+    }
+
+    @Override
+    public LPSolution solve(AbstractLPModel model) {
+        if (model == null) {
+            throw new IllegalArgumentException("model must not be null");
+        }
+        if (!model.isBuilt()) {
+            throw new IllegalStateException("Model must be built() before solving.");
+        }
+
+        if (debug) {
+            LOGGER.info(MessageFormat.format(
+                    "{0}: solving with {1} (vars={2}, cons={3})",
+                    getClass().getSimpleName(),
+                    backend.getClass().getSimpleName(),
+                    model.getVariables().size(),
+                    model.getConstraints().size()
+            ));
+        }
+
+        long t0 = System.nanoTime();
+        LPSolution sol = backend.solve(model);
+        long dtMs = (System.nanoTime() - t0) / 1_000_000L;
+
+        if (debug) {
+            LOGGER.info(MessageFormat.format(
+                    "{0}: result feasible={1}, objective={2}, time={3} ms",
+                    getClass().getSimpleName(),
+                    sol.isFeasible(),
+                    sol.getObjectiveValue(),
+                    dtMs
+            ));
+        }
+        return sol;
+    }
+}
diff --git a/src/test/java/org/simulator/optsolvx/BridgeObjectiveTest.java b/src/test/java/org/simulator/optsolvx/BridgeObjectiveTest.java
new file mode 100644
index 00000000..a52d6194
--- /dev/null
+++ b/src/test/java/org/simulator/optsolvx/BridgeObjectiveTest.java
@@ -0,0 +1,79 @@
+package org.simulator.optsolvx;
+
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+import org.optsolvx.model.AbstractLPModel;
+import org.optsolvx.solver.LPSolution;
+import org.optsolvx.solver.CommonsMathSolver;
+import org.sbml.jsbml.*;
+import org.sbml.jsbml.ext.fbc.*;
+
+public class BridgeObjectiveTest {
+
+    @Test
+    public void maps_fbc_v2_bounds_and_objective() {
+        SBMLDocument doc = new SBMLDocument(3, 2);
+        Model m = doc.createModel("toy_fbc2");
+        Compartment c = m.createCompartment("c"); c.setConstant(true); c.setSize(1.0);
+
+        Species x = m.createSpecies("X");
+        x.setCompartment("c");
+        x.setBoundaryCondition(false);
+
+        Reaction rin = m.createReaction("R_in");
+        rin.setReversible(false);
+        rin.createProduct().setSpecies("X");
+
+        Reaction rout = m.createReaction("R_out");
+        rout.setReversible(false);
+        rout.createReactant().setSpecies("X");
+
+        // --- Attach FBC v2 plugin to model and reactions
+        final String fbcNS = FBCConstants.getNamespaceURI(doc.getLevel(), doc.getVersion(), 2);
+        FBCModelPlugin fbcModel = (FBCModelPlugin) m.getPlugin(fbcNS);
+        if (fbcModel == null) {
+            fbcModel = new FBCModelPlugin(m);
+            m.addExtension(FBCConstants.shortLabel, fbcModel);
+        }
+
+        FBCReactionPlugin fbcIn = (FBCReactionPlugin) rin.getPlugin(fbcNS);
+        if (fbcIn == null) {
+            fbcIn = new FBCReactionPlugin(rin);
+            rin.addExtension(FBCConstants.shortLabel, fbcIn);
+        }
+        FBCReactionPlugin fbcOut = (FBCReactionPlugin) rout.getPlugin(fbcNS);
+        if (fbcOut == null) {
+            fbcOut = new FBCReactionPlugin(rout);
+            rout.addExtension(FBCConstants.shortLabel, fbcOut);
+        }
+
+        // Bounds via Parameters referenced by FBC (v2 style)
+        Parameter lbIn = m.createParameter("LB_IN"); lbIn.setConstant(true); lbIn.setValue(0.0);
+        Parameter ubIn = m.createParameter("UB_IN"); ubIn.setConstant(true); ubIn.setValue(10.0);
+        Parameter lbOut= m.createParameter("LB_OUT");lbOut.setConstant(true);lbOut.setValue(0.0);
+        Parameter ubOut= m.createParameter("UB_OUT");ubOut.setConstant(true);ubOut.setValue(10.0);
+
+        fbcIn.setLowerFluxBound(lbIn.getId());
+        fbcIn.setUpperFluxBound(ubIn.getId());
+        fbcOut.setLowerFluxBound(lbOut.getId());
+        fbcOut.setUpperFluxBound(ubOut.getId());
+
+        // Objective: maximize v_out
+        Objective obj = fbcModel.createObjective("obj");
+        obj.setType(Objective.Type.MAXIMIZE);
+        FluxObjective fo = obj.createFluxObjective();
+        fo.setReaction(rout.getId());
+        fo.setCoefficient(1.0);
+        fbcModel.setActiveObjective(obj.getId());
+
+        // --- Bridge & solve
+        AbstractLPModel lp = FbaToOptSolvX.fromSBML(doc);
+        LPSolution sol = new OptSolvXSolverAdapter(new CommonsMathSolver()).solve(lp);
+
+        assertTrue(sol.isFeasible());
+        assertEquals(10.0, sol.getObjectiveValue(), 1e-6); // max v_out = 10
+        assertEquals(10.0, sol.getVariableValues().get("R_in"), 1e-6);
+        assertEquals(10.0, sol.getVariableValues().get("R_out"), 1e-6);
+    }
+}
diff --git a/src/test/java/org/simulator/optsolvx/BridgeSmokeTest.java b/src/test/java/org/simulator/optsolvx/BridgeSmokeTest.java
new file mode 100644
index 00000000..970df053
--- /dev/null
+++ b/src/test/java/org/simulator/optsolvx/BridgeSmokeTest.java
@@ -0,0 +1,79 @@
+package org.simulator.optsolvx;
+
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+import org.optsolvx.model.AbstractLPModel;
+import org.optsolvx.solver.LPSolution;
+import org.optsolvx.solver.CommonsMathSolver;
+import org.sbml.jsbml.*;
+import org.sbml.jsbml.ext.fbc.*;
+
+public class BridgeSmokeTest {
+
+    @Test
+    public void maps_fbc_v2_bounds_and_objective() {
+        SBMLDocument doc = new SBMLDocument(3, 2);
+        Model m = doc.createModel("toy_fbc2");
+        Compartment c = m.createCompartment("c"); c.setConstant(true); c.setSize(1.0);
+
+        Species x = m.createSpecies("X");
+        x.setCompartment("c");
+        x.setBoundaryCondition(false);
+
+        Reaction rin = m.createReaction("R_in");
+        rin.setReversible(false);
+        rin.createProduct().setSpecies("X");
+
+        Reaction rout = m.createReaction("R_out");
+        rout.setReversible(false);
+        rout.createReactant().setSpecies("X");
+
+        // --- Attach FBC v2 plugin to model and reactions
+        final String fbcNS = FBCConstants.getNamespaceURI(doc.getLevel(), doc.getVersion(), 2);
+        FBCModelPlugin fbcModel = (FBCModelPlugin) m.getPlugin(fbcNS);
+        if (fbcModel == null) {
+            fbcModel = new FBCModelPlugin(m);
+            m.addExtension(FBCConstants.shortLabel, fbcModel);
+        }
+
+        FBCReactionPlugin fbcIn = (FBCReactionPlugin) rin.getPlugin(fbcNS);
+        if (fbcIn == null) {
+            fbcIn = new FBCReactionPlugin(rin);
+            rin.addExtension(FBCConstants.shortLabel, fbcIn);
+        }
+        FBCReactionPlugin fbcOut = (FBCReactionPlugin) rout.getPlugin(fbcNS);
+        if (fbcOut == null) {
+            fbcOut = new FBCReactionPlugin(rout);
+            rout.addExtension(FBCConstants.shortLabel, fbcOut);
+        }
+
+        // Bounds via Parameters referenced by FBC (v2 style)
+        Parameter lbIn = m.createParameter("LB_IN"); lbIn.setConstant(true); lbIn.setValue(0.0);
+        Parameter ubIn = m.createParameter("UB_IN"); ubIn.setConstant(true); ubIn.setValue(10.0);
+        Parameter lbOut= m.createParameter("LB_OUT");lbOut.setConstant(true);lbOut.setValue(0.0);
+        Parameter ubOut= m.createParameter("UB_OUT");ubOut.setConstant(true);ubOut.setValue(10.0);
+
+        fbcIn.setLowerFluxBound(lbIn.getId());
+        fbcIn.setUpperFluxBound(ubIn.getId());
+        fbcOut.setLowerFluxBound(lbOut.getId());
+        fbcOut.setUpperFluxBound(ubOut.getId());
+
+        // Objective: maximize v_out
+        Objective obj = fbcModel.createObjective("obj");
+        obj.setType(Objective.Type.MAXIMIZE);
+        FluxObjective fo = obj.createFluxObjective();
+        fo.setReaction(rout.getId());
+        fo.setCoefficient(1.0);
+        fbcModel.setActiveObjective(obj.getId());
+
+        // --- Bridge & solve
+        AbstractLPModel lp = FbaToOptSolvX.fromSBML(doc);
+        LPSolution sol = new OptSolvXSolverAdapter(new CommonsMathSolver()).solve(lp);
+
+        assertTrue(sol.isFeasible());
+        assertEquals(10.0, sol.getObjectiveValue(), 1e-6); // max v_out = 10
+        assertEquals(10.0, sol.getVariableValues().get("R_in"), 1e-6);
+        assertEquals(10.0, sol.getVariableValues().get("R_out"), 1e-6);
+    }
+}
diff --git a/src/test/java/org/simulator/optsolvx/OptSolvXSolverAdapterTest.java b/src/test/java/org/simulator/optsolvx/OptSolvXSolverAdapterTest.java
new file mode 100644
index 00000000..c36b9716
--- /dev/null
+++ b/src/test/java/org/simulator/optsolvx/OptSolvXSolverAdapterTest.java
@@ -0,0 +1,55 @@
+package org.simulator.optsolvx;
+
+import org.junit.Test;
+import static org.junit.Assert.*;
+import org.optsolvx.model.*;
+import org.optsolvx.solver.*;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class OptSolvXSolverAdapterTest {
+
+    @Test(expected = IllegalArgumentException.class)
+    public void solve_requires_non_null_model() {
+        LPSolverAdapter s = new OptSolvXSolverAdapter(new CommonsMathSolver(), false);
+        s.solve(null); // must throw
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void solve_requires_build() {
+        AbstractLPModel m = new AbstractLPModel();
+        m.addVariable("x", 0.0d, 10.0d);
+        LPSolverAdapter s = new OptSolvXSolverAdapter(new CommonsMathSolver(), false);
+        s.solve(m); // not built -> must throw
+    }
+
+    @Test
+    public void smoke_minimize_with_eq_and_bounds() {
+        // Minimize 2x + y, s.t. x + y = 5, 0 <= x,y <= 5
+        AbstractLPModel m = new AbstractLPModel();
+        m.addVariable("x", 0.0d, 5.0d);
+        m.addVariable("y", 0.0d, 5.0d);
+
+        Map<String, Double> obj = new HashMap<>();
+        obj.put("x", 2.0d);
+        obj.put("y", 1.0d);
+        m.setObjective(obj, OptimizationDirection.MINIMIZE);
+
+        Map<String, Double> eq = new HashMap<>();
+        eq.put("x", 1.0d);
+        eq.put("y", 1.0d);
+        m.addConstraint("sum", eq, Constraint.Relation.EQ, 5.0d);
+
+        m.build();
+
+        LPSolverAdapter s = new OptSolvXSolverAdapter(new CommonsMathSolver(), false);
+        LPSolution sol = s.solve(m);
+
+        assertTrue(sol.isFeasible());
+        // Optimum at x=0, y=5 -> objective = 5
+        assertEquals(5.0d, sol.getObjectiveValue(), 1e-6d);
+        assertEquals(0.0d, sol.getVariableValues().get("x"), 1e-6d);
+        assertEquals(5.0d, sol.getVariableValues().get("y"), 1e-6d);
+    }
+}