NullPointerException – generate report in jasper-Collection of common programming errors

I’m having a problem when generating reports with Jasper Reports.
My intention is to generate a report for each user, but it only generates a single pdf.

Grave: Error instantiating extensions registry for fonts
    java.lang.NullPointerException
        at net.sf.jasperreports.engine.fonts.SimpleFontFace.(SimpleFontFace.java:83)
        at net.sf.jasperreports.engine.fonts.SimpleFontFamily.createFontFace(SimpleFontFamily.java:316)
        at net.sf.jasperreports.engine.fonts.SimpleFontFamily.setItalic(SimpleFontFamily.java:101)
        at net.sf.jasperreports.engine.fonts.SimpleFontExtensionHelper.parseFontFamily(SimpleFontExtensionHelper.java:241)
        at net.sf.jasperreports.engine.fonts.SimpleFontExtensionHelper.parseFontFamilies(SimpleFontExtensionHelper.java:204)
        at net.sf.jasperreports.engine.fonts.SimpleFontExtensionHelper.loadFontFamilies(SimpleFontExtensionHelper.java:173)
        at net.sf.jasperreports.engine.fonts.SimpleFontExtensionHelper.loadFontFamilies(SimpleFontExtensionHelper.java:142)
        at net.sf.jasperreports.engine.fonts.SimpleFontExtensionsRegistryFactory.createRegistry(SimpleFontExtensionsRegistryFactory.java:63)
        at net.sf.jasperreports.extensions.DefaultExtensionsRegistry.instantiateRegistry(DefaultExtensionsRegistry.java:200)
        at net.sf.jasperreports.extensions.DefaultExtensionsRegistry.loadRegistries(DefaultExtensionsRegistry.java:175)
        at net.sf.jasperreports.extensions.DefaultExtensionsRegistry.loadRegistries(DefaultExtensionsRegistry.java:135)
        at net.sf.jasperreports.extensions.DefaultExtensionsRegistry.getRegistries(DefaultExtensionsRegistry.java:121)
        at net.sf.jasperreports.extensions.DefaultExtensionsRegistry.getExtensions(DefaultExtensionsRegistry.java:98)
        at net.sf.jasperreports.engine.util.JRStyledTextParser.(JRStyledTextParser.java:76)
        at net.sf.jasperreports.engine.fill.JRBaseFiller.(JRBaseFiller.java:181)
        at net.sf.jasperreports.engine.fill.JRVerticalFiller.(JRVerticalFiller.java:76)
        at net.sf.jasperreports.engine.fill.JRVerticalFiller.(JRVerticalFiller.java:86)
        at net.sf.jasperreports.engine.fill.JRVerticalFiller.(JRVerticalFiller.java:56)
        at net.sf.jasperreports.engine.fill.JRFiller.createFiller(JRFiller.java:142)
        at net.sf.jasperreports.engine.fill.JRFiller.fillReport(JRFiller.java:52)
        at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:417)
        at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:247)
        at sige.comunicacao.participante.ServletEmitirCertificadoTodosParticipantes.emitirCertificado(ServletEmitirCertificadoTodosParticipantes.java:250)
        at sige.comunicacao.participante.ServletEmitirCertificadoTodosParticipantes.doPost(ServletEmitirCertificadoTodosParticipantes.java:102)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:873)
        at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
        at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
        at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
        at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
        at java.lang.Thread.run(Unknown Source)

The code snippet that is generating the exception is:

  // Aqui ele cria o relatório
                        impressao = JasperFillManager.fillReport(pathJasper
                                + "/Certificado_Conclusao.jasper", parametros, con);

                        // exporta para pdf
                        JasperExportManager.exportReportToPdfFile(impressao, path
                                + "/Certificado_Conclusao_" + cpf + ".pdf");

I am using the jasper reports 3.7.2

Anyone knows how to solve this? Thank you in advance