If you are still looking. I have VB code as well.
Draw a circle on arcmap using java
static void drawCircle2(IActiveView activeView) throws Exception
{
double Px;
double Py;
double Radius;
IGraphicsContainer graphicsContainer = activeView.getGraphicsContainer();
// set up the color
IRgbColor rgbColor = new RgbColor();
rgbColor.setRed(0);
rgbColor.setGreen(255);
rgbColor.setBlue(0);
IColor color = rgbColor;
// make the line and define its color, style and width
ISimpleLineSymbol LineSymbol = new SimpleLineSymbol();
LineSymbol.setColor(color);
LineSymbol.setStyle(esriSimpleLineStyle.esriSLSSol id);
LineSymbol.setWidth(2);
ISymbol symbol = (ISymbol)LineSymbol;
//create circle element
ILineElement pCircleLineElement = new LineElement();
pCircleLineElement.setSymbol(LineSymbol);
IElement pCircleElement = (IElement)pCircleLineElement;
// create point and radius
Px = 0.0;
Py = 0.0;
Radius = 10.0;
// Create circle geometry
IPoint centerPoint = new Point();
centerPoint.putCoords(Px,Py);
IConstructCircularArc pCircularArc = new CircularArc();
pCircularArc.constructCircle(centerPoint,Radius,tr ue);
ISegment Seg = (ISegment)pCircularArc;
ISegmentCollection SegCollection = new Polyline();
SegCollection.addSegment(Seg,null,null);
pCircleElement.setGeometry((IGeometry)SegCollection);
//add the element to the map and draw it.
graphicsContainer.addElement(pCircleElement,0);
activeView.partialRefresh(esriViewDrawPhase.esriVi ewGraphics,null,null);
}