ErrorProne: fix sampler/UnnecessaryLambda

sampler/src/main/java/atlantafx/sampler/layout/Sidebar.java

@@ -33,6 +33,7 @@ import java.util.function.Predicate;
 import static javafx.scene.control.ScrollPane.ScrollBarPolicy.AS_NEEDED;
 import static javafx.scene.layout.Priority.ALWAYS;
 
+@SuppressWarnings("UnnecessaryLambda")
 class Sidebar extends StackPane {
 
     private static final PseudoClass SELECTED = PseudoClass.getPseudoClass("selected");

sampler/src/main/java/atlantafx/sampler/page/QuickConfigMenu.java

@@ -38,6 +38,7 @@ import static org.kordamp.ikonli.material2.Material2AL.ARROW_FORWARD;
 // This should really be refactored to more generic control someday.
 // - the whole component to PopoverMenu, that reuses JavaFX MenuItem API
 // - font size switcher to flat SpinnerMenuItem
+@SuppressWarnings("UnnecessaryLambda")
 public class QuickConfigMenu extends StackPane {
 
     private static final PseudoClass SELECTED = PseudoClass.getPseudoClass("selected");

sampler/src/main/java/atlantafx/sampler/page/general/ThemePage.java

@@ -31,6 +31,7 @@ import static atlantafx.sampler.page.SampleBlock.BLOCK_HGAP;
 import static atlantafx.sampler.page.SampleBlock.BLOCK_VGAP;
 import static atlantafx.sampler.util.Controls.hyperlink;
 
+@SuppressWarnings("UnnecessaryLambda")
 public class ThemePage extends AbstractPage {
 
     public static final String NAME = "Theme";

sampler/src/main/java/atlantafx/sampler/page/general/ThemeRepoManager.java

@@ -30,6 +30,7 @@ import static atlantafx.base.theme.Styles.*;
 import static javafx.scene.control.ScrollPane.ScrollBarPolicy.AS_NEEDED;
 import static javafx.scene.layout.Priority.ALWAYS;
 
+@SuppressWarnings("UnnecessaryLambda")
 class ThemeRepoManager extends VBox {
 
     private static final Executor THREAD_POOL = Executors.newFixedThreadPool(3);