File: Main.java

public class Main {
  public static void main(String[] a) {
    var obj = new Object() {
      public static final String msg = "Hello";
    };
    System.out.println(obj.msg);
  }
}

$ java Main.java
Hello

$ jshell
| Welcome to JShell -- Version 19
| For an introduction type: /help intro

jshell> var obj = new Object() {
   ...> public static final String msg = "hello";
   ...> }
| Error:
| cannot assign a value to final variable msg
| public static final String msg = "hello";
|