MySQL JDBC Error : Communications link failure

Question

I'm doing a group project with Java, JavaFX and MySQL, and I have a big problem when trying to connect to my database with JDBC. I have systematically this error thrown by DriverManager.getConnection() method :

Communications link failure 

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

EDIT: Here is the whole stack trace :

com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
        at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:175)
        at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
        at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825)
        at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:446)
        at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:239)
        at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:188)
        at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:681)
        at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:252)
        at controller.Controller.dbconnect(Controller.java:34)
        at controller.Controller.<init>(Controller.java:18)
        at App.start(App.java:15)
        at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(LauncherImpl.java:847)
        at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait$12(PlatformImpl.java:484)
        at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:457)
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
        at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:456)
        at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
        at javafx.graphics/com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
        at javafx.graphics/com.sun.glass.ui.gtk.GtkApplication.lambda$runLoop$11(GtkApplication.java:290)
        at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
        at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:77)
        at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
        at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:480)
        at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:62)
        at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
        at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:150)
        at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:166)
        at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:89)
        at com.mysql.cj.NativeSession.connect(NativeSession.java:121)
        at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:945)
        at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:815)
        ... 17 more
Caused by: java.net.ConnectException: Connection refused
        at java.base/sun.nio.ch.Net.connect0(Native Method)
        at java.base/sun.nio.ch.Net.connect(Net.java:579)
        at java.base/sun.nio.ch.Net.connect(Net.java:568)
        at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:588)
        at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:327)
        at java.base/java.net.Socket.connect(Socket.java:633)
        at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:153)
        at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:63)
        ... 20 more

The code throwing the error is :

public Connection dbconnect() {
    Connection conn = null;
    try {
      conn = DriverManager
          .getConnection(
              "jdbc:mysql://127.0.0.1:3306/cookbook?user=root&password=ABC&useSSL=false");
    } catch (SQLException e) {
      System.out.println(e.getMessage());
    }
    return conn;
  }

I'm using VSCode in Windows 10 and a Debian WSL to compile. I installed MySQL Server, Workbench and Connector/J version 8.0.33.

I already spent hours trying to fix that. It works perfectly for the other members of the group and I can connect to an online database (using this), so I can be sure that the problem comes from my machine. I found a lot of different possible causes and solutions online, so many that I could not enumerate them all but here are some :

• Disabling firewall
• Modify the jdbc URL in various ways
• Modify the my.ini file
• Reinstalling MySQL
• Downgrading MySQL
• Asserting MySQL has good permissions

(Basically everything that is contained there, and there.)

Nothing worked, I'm running out of options and ideas, so maybe you can have a new solution I never tried.