Erro com relatorio jasper + annotations

public void mostrarRelatorio() {
        try {
            
            // Um List com os registros que vêm do DAO
            CTR_ManterProfessor ctrProf = new CTR_ManterProfessor(factory);
            List<Professor> dataSource = ctrProf.listarProfessores("nome_professor");
            if (dataSource.isEmpty()){
                JOptionPane.showMessageDialog(null, "erro");
            }

            // Um HashMap com os parâmetros   
            HashMap params = new HashMap();

            // Exibicao do Relatorio   
            JRBeanCollectionDataSource ds = new JRBeanCollectionDataSource(dataSource);
            JasperReport report = (JasperReport) JRLoader.loadObject(getClass().getClassLoader().getResource("classic.jasper"));

            JasperPrint impressao = JasperFillManager.fillReport(report, params, ds);
            
            JasperViewer.viewReport(impressao, false);

            JRViewer viewer = new JRViewer(impressao);

            JFrame frameViewer = new JFrame("Relatorio");
            frameViewer.setSize(800, 600);
            frameViewer.setResizable(true);
            frameViewer.add(viewer);
            princ.setEnabled(false);
            frameViewer.setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
            frameViewer.setTitle("SPH - Relatório");
            frameViewer.addWindowListener(new java.awt.event.WindowAdapter() {

                @Override
                public void windowClosed(java.awt.event.WindowEvent evt) {
                    formWindowClosed(evt);
                }

                private void formWindowClosed(WindowEvent evt) {
                    princ.setEnabled(true);
                    princ.toFront();
                }
            });



        } catch (Exception e) {
            JOptionPane.showMessageDialog(null, "Problema ao gerar Relatorio.\n" + e.getMessage());
            e.printStackTrace();
        }
    }