Drawing a Line

I want to draw a line from the com.jme.scene.Line package, but I don’t know what some of the parameters mean.

Line

public Line(java.lang.String name,
Vector3f[] vertex,
Vector3f[] normal,
ColorRGBA[] color,
Vector2f[] texture)
Constructor instantiates a new Line object with a given set of data. Any data can be null except for the vertex list. If vertices are null an exception will be thrown.
Parameters:
name - the name of the scene element. This is required for identification and comparision purposes.
vertex - the vertices that make up the lines.
normal - the normals of the lines.
color - the color of each point of the lines.
texture - the texture coordinates of the lines.

What does it mean by the normals of the line?
and what would I put for texture?