AdvanceCache throwing NPE in headless mode

Question

Using jCharts (cross-posted there too), axisChart.render() is throwing this NullPointerException, but only some of the time. Looks like about half the time, the other half everything works great. I'm at a loss. It's a servlet that generates a JPEG chart, running in Caucho's Resin engine, 1.4 jdk running in headless mode, on a Linux box. Any ideas are appreciated...
dataSeries.addIAxisChartDataSet( new AxisChartDataSet( data, legendLabels, paints, ChartType.BAR, barChartProperties ) );
AxisChart axisChart= new AxisChart( dataSeries, chartProperties, axisProperties, legendProperties, width, height );
BufferedImage awtImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
axisChart.setGraphics2D(awtImage.createGraphics());
axisChart.render();
try {
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(response.getOutputStream());
encoder.encode(awtImage);
} catch (Exception e) {
System.out.println(e);
java.lang.NullPointerException
at sun.awt.font.AdvanceCache.get(AdvanceCache.java:125)
at java.awt.font.TextLayout$OptInfo.handleGetVisualBounds(TextLayout.java:280)
at sun.awt.font.Decoration.getVisualBounds(Decoration.java:105)
at java.awt.font.TextLayout$OptInfo.getVisualBounds(TextLayout.java:309)
at java.awt.font.TextLayout.getBounds(TextLayout.java:1109)
at org.jCharts.Chart.renderChartTitle(Unknown Source)
at org.jCharts.axisChart.AxisChart.renderChart(Unknown Source)
at org.jCharts.Chart.render(Unknown Source)
at ChartGen.doGet(ChartGen.java:76)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:126)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:103)
at com.caucho.server.http.FilterChainServlet.doFilter(FilterChainServlet.java:96)
at com.caucho.server.http.Invocation.service(Invocation.java:311)
at com.caucho.server.http.RunnerRequest.handleRequest(RunnerRequest.java:342)
at com.caucho.server.http.RunnerRequest.handleConnection(RunnerRequest.java:272)
at com.caucho.server.TcpConnection.run(TcpConnection.java:137)
at java.lang.Thread.run(Thread.java:536)

Answer 1

I'm also running into this. It seems after having Tomcat running for a while (days) it suddenly starts happening. It's as if it caches something that is then forgotten (or closed), and when called, it throws NPE. I'd love to know if this turns out to be a JDK bug or if there's a logical explanation.