Erro JasperReports

Servlet Error: : java.lang.NullPointerException
      java/awt/Font.defaultLineMetrics(Ljava/awt/font/FontRenderContext;)Ljava/awt/Font$FontLineMetrics;+30 (Font.java:1322) 
      java/awt/Font.getLineMetrics([CIILjava/awt/font/FontRenderContext;)Ljava/awt/font/LineMetrics;+1 (Font.java:1389) 
      java/awt/font/TextLine.getComponents(Ljava/awt/font/TextLine$FontSource;[CII[I[BLsun/awt/font/TextLabelFactory;)[Lsun/awt/font/TextLineComponent;+221 (TextLine.java:904) 
      java/awt/font/TextMeasurer.generateComponents(Ljava/text/AttributedCharacterIterator;)V+101 (TextMeasurer.java:149) 
      java/awt/font/TextMeasurer.initAll(Ljava/text/AttributedCharacterIterator;)V+145 (TextMeasurer.java:124) 
      java/awt/font/TextMeasurer.<init>(Ljava/text/AttributedCharacterIterator;Ljava/awt/font/FontRenderContext;)V+14 (TextMeasurer.java:87) 
      java/awt/font/LineBreakMeasurer.<init>(Ljava/text/AttributedCharacterIterator;Ljava/awt/font/FontRenderContext;)V+5 (LineBreakMeasurer.java:252) 
      net/sf/jasperreports/engine/fill/TextMeasurer.renderParagraph(Ljava/text/AttributedCharacterIterator;ILjava/lang/String;)V+0 (TextMeasurer.java:242) 
      net/sf/jasperreports/engine/fill/TextMeasurer.measure(Lnet/sf/jasperreports/engine/util/JRStyledText;Ljava/lang/String;II)V+0 (TextMeasurer.java:197) 
      net/sf/jasperreports/engine/fill/JRFillTextElement.chopTextElement(I)V+0 (JRFillTextElement.java:492) 
      net/sf/jasperreports/engine/fill/JRFillStaticText.prepare(IZ)Z+0 (JRFillStaticText.java:131) 
      net/sf/jasperreports/engine/fill/JRFillElementContainer.prepareElements(IZ)V+0 (JRFillElementContainer.java:265) 
      net/sf/jasperreports/engine/fill/JRFillBand.fill(IZ)Lnet/sf/jasperreports/engine/fill/JRPrintBand;+0 (JRFillBand.java:291) 
      net/sf/jasperreports/engine/fill/JRFillBand.fill(I)Lnet/sf/jasperreports/engine/fill/JRPrintBand;+0 (JRFillBand.java:279) 
      net/sf/jasperreports/engine/fill/JRVerticalFiller.fillColumnBand(Lnet/sf/jasperreports/engine/fill/JRFillBand;B)V+0 (JRVerticalFiller.java:1307) 
      net/sf/jasperreports/engine/fill/JRVerticalFiller.fillDetail()V+0 (JRVerticalFiller.java:607) 
      net/sf/jasperreports/engine/fill/JRVerticalFiller.fillReportStart()V+0 (JRVerticalFiller.java:210) 
      net/sf/jasperreports/engine/fill/JRVerticalFiller.fillReport()V+0 (JRVerticalFiller.java:124) 
      net/sf/jasperreports/engine/fill/JRBaseFiller.fill(Ljava/util/Map;Lnet/sf/jasperreports/engine/JRDataSource;)Lnet/sf/jasperreports/engine/JasperPrint;+0 (JRBaseFiller.java:715)