Changing the Thickness of the Stroking Pen
dashPhase is the offset to start the dashing pattern. 

 float strokeThickness = 5.0f;
     
 // A solid stroke
 BasicStroke stroke = new BasicStroke(strokeThickness);
 g2d.setStroke(stroke);
 drawShape(g2d);
     
 // A dashed stroke
 float miterLimit = 10f;
 float[] dashPattern = {10f};
 float dashPhase = 5f;
 stroke = new BasicStroke(
   strokeThickness, BasicStroke.CAP_BUTT, 
   BasicStroke.JOIN_MITER, miterLimit, 
   dashPattern, dashPhase);
 g2d.setStroke(stroke);
 drawShape(g2d);