Fixed issue where jar file does not work on macos and linux

build.gradle

@@ -1,7 +1,6 @@
 plugins {
     id 'java'
     id 'application'
-    id 'org.openjfx.javafxplugin' version '0.0.13'
     id 'com.github.johnrengelman.shadow' version '5.1.0'
     id 'checkstyle'
 }
@@ -14,7 +13,7 @@ dependencies {
     testImplementation group: 'org.junit.jupiter', name: 'junit-jupiter-api', version: '5.5.0'
     testRuntimeOnly group: 'org.junit.jupiter', name: 'junit-jupiter-engine', version: '5.5.0'
 
-    String javaFxVersion = '11.0.2'
+    String javaFxVersion = '11'
 
     implementation group: 'org.openjfx', name: 'javafx-base', version: javaFxVersion, classifier: 'win'
     implementation group: 'org.openjfx', name: 'javafx-base', version: javaFxVersion, classifier: 'mac'

src/main/java/duke/DialogBox.java

@@ -11,9 +11,8 @@
 import javafx.scene.Node;
 import javafx.scene.control.Label;
 import javafx.scene.image.Image;
+import javafx.scene.image.ImageView;
 import javafx.scene.layout.HBox;
-import javafx.scene.paint.ImagePattern;
-import javafx.scene.shape.Circle;
 
 /**
  * An example of a custom control using FXML.
@@ -24,7 +23,7 @@ public class DialogBox extends HBox {
     @FXML
     private Label dialog;
     @FXML
-    private Circle displayPicture;
+    private ImageView displayPicture;
 
     private DialogBox(String text, Image img) {
         try {
@@ -35,9 +34,8 @@ private DialogBox(String text, Image img) {
         } catch (IOException e) {
             e.printStackTrace();
         }
-
         dialog.setText(text);
-        displayPicture.setFill(new ImagePattern(img));
+        displayPicture.setImage(img);
     }
 
     /**

src/main/java/duke/MainWindow.java

@@ -1,5 +1,7 @@
 package duke;
 
+import java.util.Objects;
+
 import duke.util.Ui;
 import javafx.fxml.FXML;
 import javafx.scene.control.Button;
@@ -11,6 +13,8 @@
 import javafx.scene.layout.Priority;
 import javafx.scene.layout.VBox;
 
+
+
 /**
  * Controller for MainWindow. Provides the layout for the other controls.
  */
@@ -25,8 +29,10 @@ public class MainWindow extends AnchorPane {
     private Button sendButton;
     private Duke duke;
 
-    private final Image userImage = new Image(this.getClass().getResourceAsStream("/images/plane.jpg"));
-    private final Image dukeImage = new Image(this.getClass().getResourceAsStream("/images/doomba.jpg"));
+    private final Image userImage = new Image(
+            Objects.requireNonNull(this.getClass().getResourceAsStream("/images/plane.png")));
+    private final Image dukeImage = new Image(
+            Objects.requireNonNull(this.getClass().getResourceAsStream("/images/doomba.png")));
 
     /**
      * Sets up the GUI.

src/main/resources/view/DialogBox.fxml

@@ -2,9 +2,9 @@
 
 <?import javafx.geometry.Insets?>
 <?import javafx.scene.control.Label?>
+<?import javafx.scene.image.ImageView?>
 <?import javafx.scene.layout.HBox?>
 <?import javafx.scene.layout.Pane?>
-<?import javafx.scene.shape.Circle?>
 
 <fx:root alignment="TOP_RIGHT" maxWidth="1.7976931348623157E308" prefWidth="400.0" type="javafx.scene.layout.HBox" xmlns="http://javafx.com/javafx/" xmlns:fx="http://javafx.com/fxml/1">
     <children>
@@ -17,7 +17,7 @@
             <Insets left="5.0" right="5.0" />
          </padding>
          <children>
-            <Circle fx:id="displayPicture" fill="#ffffff00" layoutX="30.0" layoutY="30.0" radius="30.0" stroke="BLACK" strokeType="INSIDE" />
+            <ImageView fx:id="displayPicture" fitHeight="55.0" fitWidth="55.0" layoutX="3.0" layoutY="3.0" />
          </children>
       </Pane>
     </children>

src/main/resources/view/MainWindow.fxml

@@ -25,10 +25,9 @@
             </HBox>
          </bottom>
          <center>
-              <ScrollPane fx:id="scrollPane" hbarPolicy="NEVER" hvalue="1.0" prefHeight="556.0" prefWidth="450.0" vvalue="1.0" BorderPane.alignment="CENTER">
+              <ScrollPane fx:id="scrollPane" hbarPolicy="NEVER" hvalue="1.0" prefHeight="50.0" prefWidth="450.0" vvalue="1.0" BorderPane.alignment="CENTER">
                   <content>
-                      <VBox fx:id="dialogContainer" prefHeight="557.0" prefWidth="440.0" style="-fx-background-image: url('./images/wallpaper.png
-                  ')"/>
+                      <VBox fx:id="dialogContainer" prefHeight="557.0" prefWidth="440.0" style="-fx-background-image: url('./images/wallpaper.png')" />
                   </content>
               </ScrollPane>
          </center>