code: private boolean isAlone( Geometry geometryN ) {
          Coordinate[] coordinates = geometryN.getCoordinates();
          if (coordinates.length > 1) {
              Coordinate first = coordinates[0];
              Coordinate last = coordinates[coordinates.length - 1];
              for( SimpleFeature line : linesList ) {
                  Geometry lineGeom = (Geometry) line.getDefaultGeometry();
                  int numGeometries = lineGeom.getNumGeometries();
                  for( int i = 0; i < numGeometries; i++ ) {
                      Geometry subGeom = lineGeom.getGeometryN(i);
                      Coordinate[] lineCoordinates = subGeom.getCoordinates();
                      if (lineCoordinates.length < 2) {
                          continue;
                      } else {
                          Coordinate tmpFirst = lineCoordinates[0];
                          Coordinate tmpLast = lineCoordinates[lineCoordinates.length - 1];
                          if (tmpFirst.distance(first) < SAMEPOINTTHRESHOLD || tmpFirst.distance(last) < SAMEPOINTTHRESHOLD
                                  || tmpLast.distance(first) < SAMEPOINTTHRESHOLD || tmpLast.distance(last) < SAMEPOINTTHRESHOLD) {
                              return false;
                          }
                      }
                  }
              }
          }
          // 1 point line or no connection, mark it as alone for removal
          return true;
      }
docs: Checks if the given geometry is connected to any other line.
  
  @param geometryN the geometry to test.
  @return true if the geometry is alone in the space, i.e. not connected at
  one of the ends to any other geometry.