Fix NPE with UnitHelp.

game-app/game-core/src/main/java/games/strategy/engine/framework/ui/background/BackgroundTaskRunner.java

@@ -4,13 +4,16 @@
 import static com.google.common.base.Preconditions.checkState;
 
 import com.google.common.base.Throwables;
+import java.util.Optional;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Consumer;
 import java.util.function.Supplier;
 import javax.annotation.Nullable;
 import javax.swing.JFrame;
 import javax.swing.SwingUtilities;
 import javax.swing.SwingWorker;
+import lombok.Getter;
 import lombok.experimental.UtilityClass;
 import org.triplea.java.Interruptibles;
 import org.triplea.java.function.ThrowingSupplier;
@@ -19,7 +22,7 @@
 /** Provides methods for running tasks in the background to avoid blocking the UI. */
 @UtilityClass
 public final class BackgroundTaskRunner {
-  private static JFrame mainFrame;
+  @Getter private static JFrame mainFrame;
 
   public static void setMainFrame(final JFrame mainFrame) {
     checkState(BackgroundTaskRunner.mainFrame == null);
@@ -72,7 +75,16 @@ public static void runInBackground(final String message, final Runnable backgrou
    */
   public static <T> T runInBackgroundAndReturn(
       final String message, final Supplier<T> backgroundAction) throws InterruptedException {
-    return runInBackgroundAndReturn(message, backgroundAction::get, RuntimeException.class);
+    return runInBackgroundAndReturn(message, backgroundAction::get, null, RuntimeException.class);
+  }
+
+  public static <T> T runInBackgroundAndReturn(
+      Consumer<T> runOnEdtBeforeDialogClose,
+      final String message,
+      final Supplier<T> backgroundAction)
+      throws InterruptedException {
+    return runInBackgroundAndReturn(
+        message, backgroundAction::get, runOnEdtBeforeDialogClose, RuntimeException.class);
   }
 
   /**
@@ -88,6 +100,9 @@ public static <T> T runInBackgroundAndReturn(
    * @param <E> The type of exception thrown by the background action.
    * @param message The message displayed to the user while the background action is running.
    * @param backgroundAction The action to run in the background.
+   * @param runOnEdtBeforeDialogClose Work to be done on EDT with the result, before closing the
+   *     dialog. Some Swing operations can be slow (e.g. layout of lots of HTML like unit help), so
+   *     this can be used to ensure we only close the progress dialog once this work has been done.
    * @param exceptionType The type of exception thrown by the background action.
    * @return The value returned by {@code backgroundAction}.
    * @throws IllegalStateException If this method is not called from the EDT.
@@ -98,6 +113,7 @@ public static <T> T runInBackgroundAndReturn(
   public static <T, E extends Exception> T runInBackgroundAndReturn(
       final String message,
       final ThrowingSupplier<T, E> backgroundAction,
+      final Consumer<T> runOnEdtBeforeDialogClose,
       final Class<E> exceptionType)
       throws E, InterruptedException {
     checkState(SwingUtilities.isEventDispatchThread());
@@ -117,16 +133,18 @@ protected T doInBackground() throws Exception {
 
           @Override
           protected void done() {
-            waitDialog.setVisible(false);
-            waitDialog.dispose();
-
             try {
-              resultRef.set(get());
+              T t = get();
+              resultRef.set(t);
+              Optional.ofNullable(runOnEdtBeforeDialogClose).ifPresent(c -> c.accept(t));
             } catch (final ExecutionException e) {
               exceptionRef.set(e.getCause());
             } catch (final InterruptedException e) {
               Thread.currentThread().interrupt();
               exceptionRef.set(e);
+            } finally {
+              waitDialog.setVisible(false);
+              waitDialog.dispose();
             }
           }
         };

game-app/game-core/src/main/java/games/strategy/triplea/ui/menubar/help/UnitHelpMenu.java

@@ -2,7 +2,9 @@
 
 import games.strategy.engine.data.GameData;
 import games.strategy.engine.framework.ui.background.BackgroundTaskRunner;
+import games.strategy.engine.framework.ui.background.WaitDialog;
 import games.strategy.triplea.ui.UiContext;
+import java.awt.Dimension;
 import javax.swing.Action;
 import javax.swing.BorderFactory;
 import javax.swing.JDialog;
@@ -20,21 +22,26 @@ class UnitHelpMenu {
   Action buildMenu(final GameData gameData, final UiContext uiContext) {
     return SwingAction.of(
         unitHelpTitle,
-        e -> {
-          final Result<JDialog> result =
-              Interruptibles.awaitResult(
-                  () ->
-                      BackgroundTaskRunner.runInBackgroundAndReturn(
-                          "Calculating Data",
-                          () -> {
-                            String text = UnitStatsTable.getUnitStatsTable(gameData, uiContext);
-                            JEditorPane editorPane = new JEditorPane("text/html", text);
-                            editorPane.setEditable(false);
-                            JScrollPane scroll = new JScrollPane(editorPane);
-                            scroll.setBorder(BorderFactory.createEmptyBorder());
-                            return InformationDialog.createDialog(scroll, unitHelpTitle);
-                          }));
-          result.result.orElseThrow().setVisible(true);
+        event -> {
+          try {
+            BackgroundTaskRunner.runInBackgroundAndReturn(
+                UnitHelpMenu::showDialog,
+                "Calculating Data",
+                () -> UnitStatsTable.getUnitStatsTable(gameData, uiContext));
+          } catch (InterruptedException e) {
+            // Nothing to do.
+          }
         });
   }
+
+  private static void showDialog(String text) {
+    final JEditorPane editorPane = new JEditorPane();
+    editorPane.setContentType("text/html");
+    editorPane.setEditable(false);
+    final JScrollPane scroll = new JScrollPane(editorPane);
+    scroll.setBorder(BorderFactory.createEmptyBorder());
+    editorPane.setText(text);
+    editorPane.setCaretPosition(0);
+    InformationDialog.createDialog(scroll, unitHelpTitle).setVisible(true);
+  }
 }

game-app/game-headed/src/main/java/games/strategy/engine/lobby/client/login/LobbyLogin.java

@@ -235,6 +235,7 @@ private void forgotPassword(final ForgotPasswordPanel panel) {
                                   .username(panel.getUserName())
                                   .email(panel.getEmail())
                                   .build()),
+                  null,
                   IOException.class)
               .getResponseMessage();
       DialogBuilder.builder()