make(java): Update examples to use maven (#202)

* Fix RandomTsp.java

examples/java/CapacitatedVehicleRoutingProblemWithTimeWindows.java

@@ -12,8 +12,9 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-package com.google.ortools.examples;
+package com.google.ortools.java;
 
+import com.google.ortools.Loader;
 import com.google.ortools.constraintsolver.Assignment;
 import com.google.ortools.constraintsolver.FirstSolutionStrategy;
 import com.google.ortools.constraintsolver.IntVar;
@@ -50,11 +51,6 @@ class Pair<K, V> {
  * using the swig-wrapped version of the vehicle routing library in src/constraint_solver.
  */
 public class CapacitatedVehicleRoutingProblemWithTimeWindows {
-
-  static {
-    System.loadLibrary("jniortools");
-  }
-
   private static Logger logger =
       Logger.getLogger(CapacitatedVehicleRoutingProblemWithTimeWindows.class.getName());
 
@@ -289,6 +285,7 @@ public class CapacitatedVehicleRoutingProblemWithTimeWindows {
   }
 
   public static void main(String[] args) throws Exception {
+    Loader.loadNativeLibraries();
     CapacitatedVehicleRoutingProblemWithTimeWindows problem =
         new CapacitatedVehicleRoutingProblemWithTimeWindows();
     final int xMax = 20;

examples/java/FlowExample.java

@@ -10,21 +10,14 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-package com.google.ortools.examples;
+package com.google.ortools.java;
 
+import com.google.ortools.Loader;
 import com.google.ortools.graph.MaxFlow;
 import com.google.ortools.graph.MinCostFlow;
 
-/**
- * Sample showing how to model using the flow solver.
- *
- */
-
+/** Sample showing how to model using the flow solver. */
 public class FlowExample {
-  static {
-    System.loadLibrary("jniortools");
-  }
-
   private static void solveMinCostFlow() {
     System.out.println("Min Cost Flow Problem - Simple interface");
     final int numSources = 4;
@@ -83,6 +76,7 @@ public class FlowExample {
   }
 
   public static void main(String[] args) throws Exception {
+    Loader.loadNativeLibraries();
     FlowExample.solveMinCostFlow();
     FlowExample.solveMaxFlow();
   }

examples/java/IntegerProgramming.java

@@ -10,24 +10,16 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+package com.google.ortools.java;
 
-package com.google.ortools.examples;
-
+import com.google.ortools.Loader;
 import com.google.ortools.linearsolver.MPConstraint;
 import com.google.ortools.linearsolver.MPObjective;
 import com.google.ortools.linearsolver.MPSolver;
 import com.google.ortools.linearsolver.MPVariable;
 
-/**
- * Integer programming example that shows how to use the API.
- *
- */
-
+/** Integer programming example that shows how to use the API. */
 public class IntegerProgramming {
-  static {
-    System.loadLibrary("jniortools");
-  }
-
   private static void runIntegerProgrammingExample(String solverType) {
     MPSolver solver = MPSolver.createSolver(solverType);
     if (solver == null) {
@@ -79,6 +71,7 @@ public class IntegerProgramming {
   }
 
   public static void main(String[] args) throws Exception {
+    Loader.loadNativeLibraries();
     System.out.println("---- Integer programming example with SCIP (recommended) ----");
     runIntegerProgrammingExample("SCIP");
     System.out.println("---- Integer programming example with CBC ----");

examples/java/LinearAssignmentAPI.java

@@ -10,22 +10,17 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-package com.google.ortools.examples;
+package com.google.ortools.java;
 
+import com.google.ortools.Loader;
 import com.google.ortools.graph.LinearSumAssignment;
 
 /**
  * Test assignment on a 4x4 matrix. Example taken from
  *  http://www.ee.oulu.fi/~mpa/matreng/eem1_2-1.htm with kCost[0][1]
  *  modified so the optimum solution is unique.
- *
  */
-
 public class LinearAssignmentAPI {
-  static {
-    System.loadLibrary("jniortools");
-  }
-
   private static void runAssignmentOn4x4Matrix() {
     final int numSources = 4;
     final int numTargets = 4;
@@ -52,6 +47,7 @@ public class LinearAssignmentAPI {
   }
 
   public static void main(String[] args) throws Exception {
+    Loader.loadNativeLibraries();
     LinearAssignmentAPI.runAssignmentOn4x4Matrix();
   }
 }

examples/java/LinearProgramming.java

@@ -10,9 +10,9 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+package com.google.ortools.java;
 
-package com.google.ortools.examples;
-
+import com.google.ortools.Loader;
 import com.google.ortools.linearsolver.MPConstraint;
 import com.google.ortools.linearsolver.MPObjective;
 import com.google.ortools.linearsolver.MPSolver;
@@ -20,14 +20,8 @@ import com.google.ortools.linearsolver.MPVariable;
 
 /**
  * Linear programming example that shows how to use the API.
- *
  */
-
 public class LinearProgramming {
-  static {
-    System.loadLibrary("jniortools");
-  }
-
   private static void runLinearProgrammingExample(String solverType, boolean printModel) {
     MPSolver solver = MPSolver.createSolver(solverType);
     if (solver == null) {
@@ -115,6 +109,7 @@ public class LinearProgramming {
   }
 
   public static void main(String[] args) throws Exception {
+    Loader.loadNativeLibraries();
     System.out.println("---- Linear programming example with GLOP (recommended) ----");
     runLinearProgrammingExample("GLOP", true);
     System.out.println("---- Linear programming example with CLP ----");

examples/java/RabbitsPheasants.java

@@ -10,25 +10,19 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-package com.google.ortools.examples;
+package com.google.ortools.java;
 
+import com.google.ortools.Loader;
 import com.google.ortools.constraintsolver.ConstraintSolverParameters;
 import com.google.ortools.constraintsolver.DecisionBuilder;
 import com.google.ortools.constraintsolver.IntVar;
 import com.google.ortools.constraintsolver.Solver;
 import java.util.logging.Logger;
 
-/**
- * Sample showing how to model using the constraint programming solver.
- *
- */
+/** Sample showing how to model using the constraint programming solver.*/
 public class RabbitsPheasants {
   private static Logger logger = Logger.getLogger(RabbitsPheasants.class.getName());
 
-  static {
-    System.loadLibrary("jniortools");
-  }
-
   /**
    * Solves the rabbits + pheasants problem.  We are seing 20 heads
    * and 56 legs. How many rabbits and how many pheasants are we thus
@@ -55,6 +49,7 @@ public class RabbitsPheasants {
   }
 
   public static void main(String[] args) throws Exception {
+    Loader.loadNativeLibraries();
     boolean traceSearch = args.length > 0 && args[1].equals("--trace");
     RabbitsPheasants.solve(traceSearch);
   }

examples/java/RandomTsp.java

@@ -1,4 +1,3 @@
-//
 // Copyright 2010-2017 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -12,8 +11,9 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-package com.google.ortools.examples;
+package com.google.ortools.java;
 
+import com.google.ortools.Loader;
 import com.google.ortools.constraintsolver.Assignment;
 import com.google.ortools.constraintsolver.FirstSolutionStrategy;
 import com.google.ortools.constraintsolver.RoutingIndexManager;
@@ -28,11 +28,7 @@ import java.util.function.LongBinaryOperator;
 import java.util.function.LongUnaryOperator;
 import java.util.logging.Logger;
 
-class RandomTsp {
-  static {
-    System.loadLibrary("jniortools");
-  }
-
+public class RandomTsp {
   private static Logger logger =
       Logger.getLogger(RandomTsp.class.getName());
 
@@ -122,6 +118,7 @@ class RandomTsp {
   }
 
   public static void main(String[] args) throws Exception {
+    Loader.loadNativeLibraries();
     int size = 10;
     if (args.length > 0) {
       size = Integer.parseInt(args[0]);