releasing native memory in Java converters

modules/java/generator/src/java/utils+Converters.java

@@ -501,7 +501,9 @@ public class Converters {
         for (Mat mi : mats) {
             MatOfPoint pt = new MatOfPoint(mi);
             pts.add(pt);
+            mi.release();
         }
+        mats.clear();
     }
 
     // vector_vector_Point2f
@@ -517,7 +519,9 @@ public class Converters {
         for (Mat mi : mats) {
             MatOfPoint2f pt = new MatOfPoint2f(mi);
             pts.add(pt);
+            mi.release();
         }
+        mats.clear();
     }
 
     // vector_vector_Point2f
@@ -547,7 +551,9 @@ public class Converters {
         for (Mat mi : mats) {
             MatOfPoint3f pt = new MatOfPoint3f(mi);
             pts.add(pt);
+            mi.release();
         }
+        mats.clear();
     }
 
     // vector_vector_Point3f
@@ -590,7 +596,9 @@ public class Converters {
         for (Mat mi : mats) {
             MatOfKeyPoint vkp = new MatOfKeyPoint(mi);
             kps.add(vkp);
+            mi.release();
         }
+        mats.clear();
     }
 
     public static Mat vector_double_to_Mat(List<Double> ds) {
@@ -689,7 +697,9 @@ public class Converters {
         for (Mat mi : mats) {
             MatOfDMatch vdm = new MatOfDMatch(mi);
             lvdm.add(vdm);
+            mi.release();
         }
+        mats.clear();
     }
 
     // vector_vector_char
@@ -719,6 +729,8 @@ public class Converters {
             List<Byte> lb = new ArrayList<Byte>();
             Mat_to_vector_char(mi, lb);
             llb.add(lb);
+            mi.release();
         }
+        mats.clear();
     }
 }