src/main/java/org/embulk/output/PostgresUDFOutputPlugin.java in embulk-output-postgres-udf-0.1.1 vs src/main/java/org/embulk/output/PostgresUDFOutputPlugin.java in embulk-output-postgres-udf-0.1.2

@@ -137,10 +137,12 @@
 
             try (PreparedStatement stmt = this.connection.prepareCall(getFunctionName(), schema)) {
                 while (pageReader.nextRecord()) {
                     for (int i = 0; i < schema.getColumnCount(); i++) {
                         Class<?> type = schema.getColumnType(i).getJavaType();
-                        if (type.equals(boolean.class)) {
+                        if (pageReader.isNull(i)) {
+                            stmt.setObject(i + 1, null);
+                        } else if (type.equals(boolean.class)) {
                             stmt.setBoolean(i + 1, pageReader.getBoolean(i));
                         } else if (type.equals(double.class)) {
                             stmt.setDouble(i + 1, pageReader.getDouble(i));
                         } else if (type.equals(long.class)) {
                             stmt.setLong(i + 1, pageReader.getLong(i));