fix: build

HMCLCore/src/test/java/org/jackhuang/hmcl/util/TaskTest.java

@@ -17,7 +17,6 @@
  */
 package org.jackhuang.hmcl.util;
 
-import javafx.embed.swing.JFXPanel;
 import org.jackhuang.hmcl.task.Schedulers;
 import org.jackhuang.hmcl.task.Task;
 import org.jackhuang.hmcl.task.TaskExecutor;
@@ -26,6 +25,9 @@ import org.junit.Assert;
 import org.junit.Assume;
 import org.junit.Test;
 
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CountDownLatch;
@@ -78,7 +80,20 @@ public class TaskTest {
     }
 
     public void testThenAccept() {
-        new JFXPanel(); // init JavaFX Toolkit
+        // init JavaFX Toolkit
+        try {
+            // Java 9 or Latter
+            final MethodHandle startup =
+                    MethodHandles.publicLookup().findStatic(
+                            javafx.application.Platform.class, "startup", MethodType.methodType(void.class, Runnable.class));
+            startup.invokeExact((Runnable) () -> {});
+        } catch (Throwable e) {
+            // Java 8
+            try {
+                Class.forName("javafx.embed.swing.JFXPanel").getDeclaredConstructor().newInstance();
+            } catch (Throwable ignored) {
+            }
+        }
         AtomicBoolean flag = new AtomicBoolean();
         boolean result = Task.supplyAsync(JavaVersion::fromCurrentEnvironment)
                 .thenAcceptAsync(Schedulers.javafx(), javaVersion -> {