调试显示Ikonli错误

Question

我的程序似乎正常运行，尽管我看到以下错误。我不喜欢忽略错误，所以我错过了什么吗？：

Could not instrument class org/kordamp/ikonli/javafx/FontIcon: null.
Could not instrument class org/kordamp/ikonli/javafx/FontIcon$1: null.
Could not instrument class org/kordamp/ikonli/javafx/FontIcon$2: null.
Could not instrument class org/kordamp/ikonli/javafx/FontIcon$3: null.
Could not instrument class org/kordamp/ikonli/javafx/FontIcon$StyleableProperties: null.
Could not instrument class org/kordamp/ikonli/javafx/FontIcon$StyleableProperties$1: null.
Could not instrument class org/kordamp/ikonli/javafx/FontIcon$StyleableProperties$2: null.
Could not instrument class org/kordamp/ikonli/javafx/FontIcon$StyleableProperties$3: null.
Could not instrument class org/kordamp/ikonli/javafx/FontIconConverter: null.
Could not instrument class org/kordamp/ikonli/javafx/FontIconConverter$Holder: null.
Could not instrument class org/kordamp/ikonli/javafx/FontIconConverter$SequenceConverter: null.

我正在使用Java 11和scene-builder，并配置了运行，如下所示： --module-path /home/rod/Downloads/javafx-sdk-11.0.2/lib --add-modules = javafx.controls，javafx.fxml。

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.ColumnConstraints?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.layout.Pane?>
<?import javafx.scene.layout.RowConstraints?>
<?import javafx.scene.text.Font?>
<?import org.kordamp.ikonli.javafx.FontIcon?>

<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="807.0" prefWidth="1128.0" style="-fx-background-color: #CFD3D4;" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="org.optaplanner.examples.view.MainController">
   <children>
      <Pane prefHeight="173.0" prefWidth="980.0" style="-fx-background-color: #2D75E8;" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
         <children>
            <Label layoutX="130.0" layoutY="44.0" text="NeoPlexus Beta Verson 1.0" textFill="WHITE">
               <font>
                  <Font size="48.0" />
               </font>
            </Label>
            <Label layoutX="136.0" layoutY="105.0" text="Staff Rostering" textFill="WHITE">
               <font>
                  <Font size="19.0" />
               </font>
            </Label>
         </children>
      </Pane>
      <GridPane alignment="CENTER" hgap="10.0" layoutX="128.0" layoutY="228.0" prefHeight="426.0" prefWidth="746.0" vgap="10.0" AnchorPane.leftAnchor="128.0" AnchorPane.rightAnchor="140.0">
        <columnConstraints>
          <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
          <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
            <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
        </columnConstraints>
        <rowConstraints>
          <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
          <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
        </rowConstraints>
         <children>
            <Button fx:id="btnEmployees" contentDisplay="TOP" mnemonicParsing="false" onAction="#handleButtonClicks" prefHeight="181.0" prefWidth="242.0" style="-fx-background-color: #F7A8E5;" text="Employees">
               <graphic>

               </graphic>
               <graphic>
                  <FontIcon iconLiteral="ion-ios-people" iconSize="50" />
               </graphic></Button>
            <Button fx:id="btnScheduleRun" contentDisplay="TOP" mnemonicParsing="false" onAction="#handleButtonClicks" prefHeight="181.0" prefWidth="242.0" style="-fx-background-color: #E64764;" text="Schedule Run" GridPane.columnIndex="2">
               <graphic>
                  <FontIcon iconLiteral="mdi-calendar-clock" iconSize="60" />
               </graphic></Button>
            <Button fx:id="btnSettings" contentDisplay="TOP" mnemonicParsing="false" onAction="#handleButtonClicks" prefHeight="181.0" prefWidth="242.0" style="-fx-background-color: #8AC5D1;" text="Settings" textFill="#0d0d0d" GridPane.rowIndex="1">
               <graphic>
                  <FontIcon iconLiteral="fa-cogs" iconSize="50" />
               </graphic></Button>
            <Button fx:id="btnSchedInitialise" contentDisplay="TOP" mnemonicParsing="false" onAction="#handleButtonClicks" prefHeight="181.0" prefWidth="242.0" style="-fx-background-color: #F2BB5c;" text="Schedule Date Initialiser" GridPane.columnIndex="1" GridPane.rowIndex="1">
               <graphic>
                  <FontIcon iconLiteral="fa-calendar-check-o" iconSize="50" />
               </graphic></Button>
            <Button fx:id="btnShiftRequest" contentDisplay="TOP" mnemonicParsing="false" onAction="#handleButtonClicks" prefHeight="181.0" prefWidth="242.0" style="-fx-background-color: AA8AD1;" text="Shift Requests" GridPane.columnIndex="1">
               <graphic>
                  <FontIcon iconLiteral="fa-clock-o" iconSize="50" />
               </graphic></Button>
            <Button fx:id="btnExport" contentDisplay="TOP" mnemonicParsing="false" prefHeight="181.0" prefWidth="242.0" style="-fx-background-color: #a1d490;" text="Not used here" GridPane.columnIndex="2" GridPane.rowIndex="1">
               <graphic>
                  <FontIcon iconLiteral="fa-times-circle" iconSize="50" />
               </graphic></Button>
         </children>
      </GridPane>
   </children>
</AnchorPane>