What is the unit of getLength() method of com.vividsolutions.jts.geom.Geometry

Question

I am using Hibernate Spatial for developing a Web Application. I have MULTILINESTRING type Geometry and calculating length of the Geometry with geometry.getLength() in the following code snippet:

//Returns a Geometry object of MULTILINESTRING type.
Geometry linegeom = routes.oltontShortestPath(oltlat,oltlong,ontlat,ontlong);
double length = linegeom.getLength();

Now the question is what is the unit of "length"? How can I get the length in meter?