code: public static STRtree geometriesToSRTree( List<Geometry> geometries ) {
          STRtree tree = new STRtree();
          for( Geometry geometry : geometries ) {
              tree.insert(geometry.getEnvelopeInternal(), geometry);
          }
          return tree;
      }
docs: Pack a list of geometries in a {@link STRtree}.
  
  <p>Note that the tree can't be modified once the query method has been called first.</p>
  
  @param geometries the list of geometries.
  @return the {@link STRtree}.