Program: 85852
Project: 85852
Buggy source:
/** 
 * Draws the item (first pass). This method draws the lines connecting the items. Instead of drawing separate lines, a GeneralPath is constructed and drawn at the end of the series painting.
 * @param g2  the graphics device.
 * @param state  the renderer state.
 * @param plot  the plot (can be used to obtain standard color informationetc).
 * @param dataset  the dataset.
 * @param pass  the pass.
 * @param series  the series index (zero-based).
 * @param item  the item index (zero-based).
 * @param domainAxis  the domain axis.
 * @param rangeAxis  the range axis.
 * @param dataArea  the area within which the data is being drawn.
 */
@Override protected void drawPrimaryLineAsPath(XYItemRendererState state,Graphics2D g2,XYPlot plot,XYDataset dataset,int pass,int series,int item,ValueAxis domainAxis,ValueAxis rangeAxis,Rectangle2D dataArea){
  RectangleEdge xAxisLocation=plot.getDomainAxisEdge();
  RectangleEdge yAxisLocation=plot.getRangeAxisEdge();
  double x1=dataset.getXValue(series,item);
  double y1=dataset.getYValue(series,item);
  double transX1=domainAxis.valueToJava2D(x1,dataArea,xAxisLocation);
  double transY1=rangeAxis.valueToJava2D(y1,dataArea,yAxisLocation);
  if (!Double.isNaN(transX1) && !Double.isNaN(transY1)) {
    ControlPoint p=new ControlPoint(plot.getOrientation() == PlotOrientation.HORIZONTAL ? (float)transY1 : (float)transX1,plot.getOrientation() == PlotOrientation.HORIZONTAL ? (float)transX1 : (float)transY1);
    if (!this.points.contains(p)) {
      this.points.add(p);
    }
  }
  if (item == dataset.getItemCount(series) - 1) {
    State s=(State)state;
    if (this.points.size() > 1) {
      ControlPoint cp0=(ControlPoint)this.points.get(0);
      s.seriesPath.moveTo(cp0.x,cp0.y);
      if (this.points.size() == 2) {
        ControlPoint cp1=(ControlPoint)this.points.get(1);
        s.seriesPath.lineTo(cp1.x,cp1.y);
      }
 else {
        int np=this.points.size();
        float[] d=new float[np];
        float[] x=new float[np];
        float y;
        float t;
        float oldy=0;
        float oldt=0;
        float[] a=new float[np];
        float t1;
        float t2;
        float[] h=new float[np];
        for (int i=0; i < np; i++) {
          ControlPoint cpi=(ControlPoint)this.points.get(i);
          x[i]=cpi.x;
          d[i]=cpi.y;
        }
        for (int i=1; i <= np - 1; i++) {
          h[i]=x[i] - x[i - 1];
        }
        float[] sub=new float[np - 1];
        float[] diag=new float[np - 1];
        float[] sup=new float[np - 1];
        for (int i=1; i <= np - 2; i++) {
          diag[i]=(h[i] + h[i + 1]) / 3;
          sup[i]=h[i + 1] / 6;
          sub[i]=h[i] / 6;
          a[i]=(d[i + 1] - d[i]) / h[i + 1] - (d[i] - d[i - 1]) / h[i];
        }
        solveTridiag(sub,diag,sup,a,np - 2);
        oldt=x[0];
        oldy=d[0];
        s.seriesPath.moveTo(oldt,oldy);
        for (int i=1; i <= np - 1; i++) {
          for (int j=1; j <= this.precision; j++) {
            t1=(h[i] * j) / this.precision;
            t2=h[i] - t1;
            y=((-a[i - 1] / 6 * (t2 + h[i]) * t1 + d[i - 1]) * t2 + (-a[i] / 6 * (t1 + h[i]) * t2 + d[i]) * t1) / h[i];
            t=x[i - 1] + t1;
            s.seriesPath.lineTo(t,y);
          }
        }
      }
      drawFirstPassShape(g2,pass,series,item,s.seriesPath);
    }
    this.points=new Vector();
  }
}

Fixed version (ground truth):
/** 
 * Draws the item (first pass). This method draws the lines connecting the items. Instead of drawing separate lines, a GeneralPath is constructed and drawn at the end of the series painting.
 * @param g2  the graphics device.
 * @param state  the renderer state.
 * @param plot  the plot (can be used to obtain standard color informationetc).
 * @param dataset  the dataset.
 * @param pass  the pass.
 * @param series  the series index (zero-based).
 * @param item  the item index (zero-based).
 * @param domainAxis  the domain axis.
 * @param rangeAxis  the range axis.
 * @param dataArea  the area within which the data is being drawn.
 */
@Override protected void drawPrimaryLineAsPath(XYItemRendererState state,Graphics2D g2,XYPlot plot,XYDataset dataset,int pass,int series,int item,ValueAxis domainAxis,ValueAxis rangeAxis,Rectangle2D dataArea){
  RectangleEdge xAxisLocation=plot.getDomainAxisEdge();
  RectangleEdge yAxisLocation=plot.getRangeAxisEdge();
  double x1=dataset.getXValue(series,item);
  double y1=dataset.getYValue(series,item);
  double transX1=domainAxis.valueToJava2D(x1,dataArea,xAxisLocation);
  double transY1=rangeAxis.valueToJava2D(y1,dataArea,yAxisLocation);
  if (!Double.isNaN(transX1) && !Double.isNaN(transY1)) {
    ControlPoint p=new ControlPoint(plot.getOrientation() == PlotOrientation.HORIZONTAL ? (float)transY1 : (float)transX1,plot.getOrientation() == PlotOrientation.HORIZONTAL ? (float)transX1 : (float)transY1);
    if (!this.points.contains(p)) {
      this.points.add(p);
    }
  }
  if (item == dataset.getItemCount(series) - 1) {
    State s=(State)state;
    if (this.points.size() > 1) {
      ControlPoint cp0=this.points.get(0);
      s.seriesPath.moveTo(cp0.x,cp0.y);
      if (this.points.size() == 2) {
        ControlPoint cp1=this.points.get(1);
        s.seriesPath.lineTo(cp1.x,cp1.y);
      }
 else {
        int np=this.points.size();
        float[] d=new float[np];
        float[] x=new float[np];
        float y;
        float t;
        float oldy=0;
        float oldt=0;
        float[] a=new float[np];
        float t1;
        float t2;
        float[] h=new float[np];
        for (int i=0; i < np; i++) {
          ControlPoint cpi=this.points.get(i);
          x[i]=cpi.x;
          d[i]=cpi.y;
        }
        for (int i=1; i <= np - 1; i++) {
          h[i]=x[i] - x[i - 1];
        }
        float[] sub=new float[np - 1];
        float[] diag=new float[np - 1];
        float[] sup=new float[np - 1];
        for (int i=1; i <= np - 2; i++) {
          diag[i]=(h[i] + h[i + 1]) / 3;
          sup[i]=h[i + 1] / 6;
          sub[i]=h[i] / 6;
          a[i]=(d[i + 1] - d[i]) / h[i + 1] - (d[i] - d[i - 1]) / h[i];
        }
        solveTridiag(sub,diag,sup,a,np - 2);
        oldt=x[0];
        oldy=d[0];
        s.seriesPath.moveTo(oldt,oldy);
        for (int i=1; i <= np - 1; i++) {
          for (int j=1; j <= this.precision; j++) {
            t1=(h[i] * j) / this.precision;
            t2=h[i] - t1;
            y=((-a[i - 1] / 6 * (t2 + h[i]) * t1 + d[i - 1]) * t2 + (-a[i] / 6 * (t1 + h[i]) * t2 + d[i]) * t1) / h[i];
            t=x[i - 1] + t1;
            s.seriesPath.lineTo(t,y);
          }
        }
      }
      drawFirstPassShape(g2,pass,series,item,s.seriesPath);
    }
    this.points=new ArrayList<ControlPoint>();
  }
}