Migrate to openJDK 13 and openJFX 13

I had to switch to openJDK coming from JDK8 and I am not able to compile my program with maven. This is new to me and after days of googling I am more confused about the versions than I was before.

I could not find out:

• Am I supposed to use the latest version of openJDK? (which is currently 13)
• Does the openJFX has to match the version of openJDK?
• Maven: Do I have to compile it with source and target with 13 or is it possible with 1.8 to be compatible with JRE1.8

Here is what I did in Eclipse

• imported openJDK 13 into eclipse and set it as the default JDK.
• updated the pom.xml to maven compiler 3.8.1 and set the source and target to 13.
• added openJFX 13 dependencies

When I freshly import the project from GIT it runs without any errors. After I compile it or update the project via Maven I get a bunch of different errors and the program is not runnable anymore. I noticed that maven sets my Project JRE to [J2SE-1.5] every time I update it. How do I prevent this?

This is really strange. Inside Class I get compiler erros that something cannot be found, but in my package explorer everything seems fine:

Snapshot

pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>IBE_Calculator</groupId>
  <artifactId>IBE_Calculator</artifactId>
  <version>IBE</version>


  <build>
    <sourceDirectory>src</sourceDirectory>
    <resources>
      <resource>
        <directory>src</directory>
        <excludes>
          <exclude>**/*.java</exclude>
        </excludes>
      </resource>

      <resource>
        <directory>main/resources</directory>
        <includes>
            <include>IBEDB.sqlite</include>        
        </includes>
      </resource>

      <resource>
        <directory>res</directory>
            <excludes>
              <exclude>**/*.java</exclude>
            </excludes>
        </resource>
    </resources>

        <pluginManagement>
      <plugins>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.1</version>
        </plugin>
      </plugins>
    </pluginManagement>

    <plugins>
        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
              <source>13</source>
              <target>13</target>
            </configuration>
        </plugin>


        <plugin>
             <artifactId>maven-assembly-plugin</artifactId>
             <configuration>
                 <archive>
                     <manifest>
                         <mainClass>main.java.srcMain.Main</mainClass>
                     </manifest>
                 </archive>
                 <descriptorRefs>
                     <descriptorRef>jar-with-dependencies</descriptorRef>
                 </descriptorRefs>
             </configuration>
             <executions>
                 <execution>
                     <phase>install</phase>
                     <goals>
                         <goal>single</goal>
                     </goals>
                 </execution>
             </executions>
         </plugin>

        <plugin>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-maven-plugin</artifactId>
            <version>0.0.3</version>
            <configuration>
                <mainClass>main.java.srcMain.Main</mainClass>
            </configuration>
        </plugin>

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <executions>
                <execution>
                    <id>copy-dependencies</id>
                    <phase>prepare-package</phase>
                    <goals>
                        <goal>copy-dependencies</goal>
                    </goals>
                    <configuration>
                        <outputDirectory>${project.build.directory}/classes/libs2</outputDirectory>
                        <overWriteReleases>false</overWriteReleases>
                        <overWriteSnapshots>false</overWriteSnapshots>
                        <overWriteIfNewer>true</overWriteIfNewer>
                    </configuration>
                </execution>
            </executions>
        </plugin>    
    </plugins>
  </build>

    <dependencies>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-base</artifactId>
            <version>13</version>
        </dependency>

        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-graphics</artifactId>
            <version>13</version>
        </dependency>

        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-fxml</artifactId>
            <version>13</version>
        </dependency>

        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-controls</artifactId>
            <version>13</version>
        </dependency>

        <dependency>
            <groupId>net.sourceforge.jexcelapi</groupId>
            <artifactId>jxl</artifactId>
            <version>2.6.12</version>
        </dependency>

        <dependency>
            <groupId>org.xerial</groupId>
            <artifactId>sqlite-jdbc</artifactId>
            <version>3.8.11.2</version>
        </dependency>

        <dependency>
            <groupId>org.dom4j</groupId>
            <artifactId>dom4j</artifactId>
            <version>2.0.1</version>
        </dependency>

        <dependency>
            <groupId>org.jgrapht</groupId>
            <artifactId>jgrapht-ext</artifactId>
            <version>1.0.1</version>
        </dependency>

        <dependency>
            <groupId>net.sourceforge.jexcelapi</groupId>
            <artifactId>jxl</artifactId>
            <version>2.6.12</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.9</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>3.9</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml-schemas</artifactId>
            <version>3.9</version>
        </dependency>

        <dependency>
            <groupId>org.apache.xmlbeans</groupId>
            <artifactId>xmlbeans</artifactId>
            <version>2.5.0</version>
        </dependency>
     </dependencies>

    <name>IBECalc</name>
</project>

I feel like theres nothing wrong with my code but here is the current error:

Exception in Application start method
Exception in thread "main" java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:900)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(LauncherImpl.java:195)
    at java.base/java.lang.Thread.run(Thread.java:830)
Caused by: java.lang.Error: Unresolved compilation problems: 
    The method handle(WindowEvent) of type new EventHandler<WindowEvent>(){} must override a superclass method
    The method run() of type new Runnable(){} must override a superclass method

    at srcMain.Main$1.handle(Main.java:42)
    at srcMain.Main$1.handle(Main.java:1)
    at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
    at javafx.event.Event.fireEvent(Event.java:198)
    at javafx.stage.Window.fireEvent(Window.java:1368)
    at javafx.stage.Window$12.invalidated(Window.java:1122)
    at javafx.beans.property.BooleanPropertyBase.markInvalid(BooleanPropertyBase.java:110)
    at javafx.beans.property.BooleanPropertyBase.set(BooleanPropertyBase.java:145)
    at javafx.stage.Window.setShowing(Window.java:1174)
    at javafx.stage.Window.show(Window.java:1189)
    at javafx.stage.Stage.show(Stage.java:273)
    at srcMain.Main.start(Main.java:74)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(LauncherImpl.java:846)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$12(PlatformImpl.java:455)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:428)
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:427)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174)
    ... 1 more

I call my Main class from a new Class, because there seems to be a bug.

Class NewMain:

package srcMain;

public class NewMain {

    public static void main(String args[] ) throws Exception {
        Main.main(args);
    }
}

Class Main:

package srcMain;
import java.io.IOException;

import java.sql.SQLException;
import java.text.ParseException;

import SQLite.*;

import javafx.application.*;
import com.sun.javafx.application.*;

import javafx.stage.Stage;
import javafx.stage.WindowEvent;
import javafx.event.*;
import javafx.fxml.FXMLLoader;
import javafx.scene.*;



public class Main extends Application{
    static SQLite db;
    public static Boolean isSplashLoaded = false;
    public static Boolean data_fin = false;
    public static Stage parentWindow;
    Stage stage = new Stage();

    @Override
    public void start(final Stage primaryStage) throws Exception{
        /*
         * �ffnet den Loading Screen und startet die Dateneinlesung
         */
        try{

            parentWindow = primaryStage;
            FXMLLoader loader = new FXMLLoader(getClass().getResource("IBE_LoadScreen.fxml"));
            loader.setController(new ControllerLoadScreen());
            Parent root1 = (Parent)loader.load();

            //wenn die GUI angezeigt wird, wird die Dateneinlesung gestartet
            stage.addEventHandler(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>() {
                @Override
                public void handle(WindowEvent window){
                    Platform.runLater(new Runnable(){
                        @Override
                        public void run(){
                            try {
                                try {
                                    readData();
                                } catch (ParseException e) {
                                    // TODO Auto-generated catch block
                                    e.printStackTrace();
                                }
                            } catch (SQLException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            }
                            data_fin = true;
                        }
                    });
                }
            });

            //wird der Close-Button gefr�ckt, schlie�t sich das gesamte Programm, nicht nur das Fenster
            Platform.setImplicitExit(false);
            stage.setOnCloseRequest(new EventHandler<WindowEvent>() {
                @Override
                public void handle(WindowEvent event) {
                    Platform.exit();
                }
            });
            stage.setResizable(true);
            stage.setTitle("Wegeentgelt-Kalkulator");
            stage.setScene(new Scene(root1));
            stage.show();
        }catch(Exception e){
            System.out.println("Cant load new window");
            e.printStackTrace();
        }

    }


    public void readData() throws SQLException, ParseException {
        /*
         * erstellt ein ExcelHandler Objekt und ruft alle Methoden auf
         * die Daten von den Excel-Files einlesen.
         * 
         * Wenn diese Daten fertig eingelesen wurden, wird die Main-Maske angezeigt.
         */

        db.Hst();
        db.Halte();
        db.Marktsegment();
        db.bstn();
        db.basisdaten();
        db.TFZ();

        db.closeConnection();
        data_fin = true;

        //wenn die Daten eingelesen wurden �ffnet sich die Main-Maske
        if(data_fin){
            FXMLLoader loader = new FXMLLoader(getClass().getResource("IBECalc-Main_1024_768.fxml"));
            loader.setController(new ControllerMain("1024x768"));
            Parent root1;
            try {
                root1 = (Parent)loader.load();
                stage.getScene().setRoot(root1);
                stage.setResizable(true);
                stage.setMinHeight(680);
                stage.setMinWidth(1024);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }


    public static void main(String[] args)  throws SQLException{
        //startet das Programm
        db = new SQLite();

        launch(args);



    }
}

I imported the project to another environment and now there is a new Error. It can't find the Application Class to start the GUI.

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
    The method launch(String[]) is undefined for the type Main

    at srcMain.Main.main(Main.java:123)
    at srcMain.NewMain.main(NewMain.java:6)