use lambdas for listeners (where possible) instead of extending Basic*UI.*Handler classes

some of those `Basic*UI.*Handler` classes may be deprecated in a future Java version (see https://github.com/openjdk/jdk/pull/1958)

this should also avoid loading of those `Basic*UI.*Handler` classes at runtime

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatComboBoxUI.java

@@ -38,7 +38,6 @@ import java.awt.event.MouseAdapter;
 import java.awt.event.MouseEvent;
 import java.awt.event.MouseListener;
 import java.awt.geom.Rectangle2D;
-import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 import java.lang.ref.WeakReference;
 import javax.swing.AbstractAction;
@@ -274,30 +273,28 @@ public class FlatComboBoxUI
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener() {
-		return new BasicComboBoxUI.PropertyChangeHandler() {
-			@Override
-			public void propertyChange( PropertyChangeEvent e ) {
-				super.propertyChange( e );
+		PropertyChangeListener superListener = super.createPropertyChangeListener();
+		return e -> {
+			superListener.propertyChange( e );
 
-				Object source = e.getSource();
-				String propertyName = e.getPropertyName();
+			Object source = e.getSource();
+			String propertyName = e.getPropertyName();
 
-				if( editor != null &&
-					((source == comboBox && propertyName == "foreground") ||
-					 (source == editor && propertyName == "enabled")) )
-				{
-					// fix editor component colors
-					updateEditorColors();
-				} else if( editor != null && source == comboBox && propertyName == "componentOrientation" ) {
-					ComponentOrientation o = (ComponentOrientation) e.getNewValue();
-					editor.applyComponentOrientation( o );
-				} else if( editor != null && FlatClientProperties.PLACEHOLDER_TEXT.equals( propertyName ) )
-					editor.repaint();
-				else if( FlatClientProperties.COMPONENT_ROUND_RECT.equals( propertyName ) )
-					comboBox.repaint();
-				else if( FlatClientProperties.MINIMUM_WIDTH.equals( propertyName ) )
-					comboBox.revalidate();
-			}
+			if( editor != null &&
+				((source == comboBox && propertyName == "foreground") ||
+				 (source == editor && propertyName == "enabled")) )
+			{
+				// fix editor component colors
+				updateEditorColors();
+			} else if( editor != null && source == comboBox && propertyName == "componentOrientation" ) {
+				ComponentOrientation o = (ComponentOrientation) e.getNewValue();
+				editor.applyComponentOrientation( o );
+			} else if( editor != null && FlatClientProperties.PLACEHOLDER_TEXT.equals( propertyName ) )
+				editor.repaint();
+			else if( FlatClientProperties.COMPONENT_ROUND_RECT.equals( propertyName ) )
+				comboBox.repaint();
+			else if( FlatClientProperties.MINIMUM_WIDTH.equals( propertyName ) )
+				comboBox.revalidate();
 		};
 	}
 
@@ -648,14 +645,12 @@ public class FlatComboBoxUI
 
 		@Override
 		protected PropertyChangeListener createPropertyChangeListener() {
-			return new BasicComboPopup.PropertyChangeHandler() {
-				@Override
-				public void propertyChange( PropertyChangeEvent e ) {
-					super.propertyChange( e );
+			PropertyChangeListener superListener = super.createPropertyChangeListener();
+			return e -> {
+				superListener.propertyChange( e );
 
-					if( e.getPropertyName() == "renderer" )
-						list.setCellRenderer( new PopupListCellRenderer() );
-				}
+				if( e.getPropertyName() == "renderer" )
+					list.setCellRenderer( new PopupListCellRenderer() );
 			};
 		}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatScrollBarUI.java

@@ -23,7 +23,6 @@ import java.awt.Insets;
 import java.awt.Rectangle;
 import java.awt.event.MouseAdapter;
 import java.awt.event.MouseEvent;
-import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 import java.util.Objects;
 import javax.swing.InputMap;
@@ -168,30 +167,28 @@ public class FlatScrollBarUI
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener() {
-		return new BasicScrollBarUI.PropertyChangeHandler() {
-			@Override
-			public void propertyChange( PropertyChangeEvent e ) {
-				super.propertyChange( e );
+		PropertyChangeListener superListener = super.createPropertyChangeListener();
+		return e -> {
+			superListener.propertyChange( e );
 
-				switch( e.getPropertyName() ) {
-					case FlatClientProperties.SCROLL_BAR_SHOW_BUTTONS:
-						scrollbar.revalidate();
-						scrollbar.repaint();
-						break;
+			switch( e.getPropertyName() ) {
+				case FlatClientProperties.SCROLL_BAR_SHOW_BUTTONS:
+					scrollbar.revalidate();
+					scrollbar.repaint();
+					break;
 
-					case "componentOrientation":
-						// this is missing in BasicScrollBarUI.Handler.propertyChange()
-						InputMap inputMap = (InputMap) UIManager.get( "ScrollBar.ancestorInputMap" );
-						if( !scrollbar.getComponentOrientation().isLeftToRight() ) {
-							InputMap rtlInputMap = (InputMap) UIManager.get( "ScrollBar.ancestorInputMap.RightToLeft" );
-							if( rtlInputMap != null ) {
-								rtlInputMap.setParent( inputMap );
-								inputMap = rtlInputMap;
-							}
+				case "componentOrientation":
+					// this is missing in BasicScrollBarUI.Handler.propertyChange()
+					InputMap inputMap = (InputMap) UIManager.get( "ScrollBar.ancestorInputMap" );
+					if( !scrollbar.getComponentOrientation().isLeftToRight() ) {
+						InputMap rtlInputMap = (InputMap) UIManager.get( "ScrollBar.ancestorInputMap.RightToLeft" );
+						if( rtlInputMap != null ) {
+							rtlInputMap.setParent( inputMap );
+							inputMap = rtlInputMap;
 						}
-						SwingUtilities.replaceUIInputMap( scrollbar, JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, inputMap );
-						break;
-				}
+					}
+					SwingUtilities.replaceUIInputMap( scrollbar, JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, inputMap );
+					break;
 			}
 		};
 	}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatScrollPaneUI.java

@@ -105,19 +105,17 @@ public class FlatScrollPaneUI
 
 	@Override
 	protected MouseWheelListener createMouseWheelListener() {
-		return new BasicScrollPaneUI.MouseWheelHandler() {
-			@Override
-			public void mouseWheelMoved( MouseWheelEvent e ) {
-				if( isSmoothScrollingEnabled() &&
-					scrollpane.isWheelScrollingEnabled() &&
-					e.getScrollType() == MouseWheelEvent.WHEEL_UNIT_SCROLL &&
-					e.getPreciseWheelRotation() != 0 &&
-					e.getPreciseWheelRotation() != e.getWheelRotation() )
-				{
-					mouseWheelMovedSmooth( e );
-				} else
-					super.mouseWheelMoved( e );
-			}
+		MouseWheelListener superListener = super.createMouseWheelListener();
+		return e -> {
+			if( isSmoothScrollingEnabled() &&
+				scrollpane.isWheelScrollingEnabled() &&
+				e.getScrollType() == MouseWheelEvent.WHEEL_UNIT_SCROLL &&
+				e.getPreciseWheelRotation() != 0 &&
+				e.getPreciseWheelRotation() != e.getWheelRotation() )
+			{
+				mouseWheelMovedSmooth( e );
+			} else
+				superListener.mouseWheelMoved( e );
 		};
 	}
 
@@ -239,41 +237,39 @@ public class FlatScrollPaneUI
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener() {
-		return new BasicScrollPaneUI.PropertyChangeHandler() {
-			@Override
-			public void propertyChange( PropertyChangeEvent e ) {
-				super.propertyChange( e );
+		PropertyChangeListener superListener = super.createPropertyChangeListener();
+		return e -> {
+			superListener.propertyChange( e );
 
-				switch( e.getPropertyName() ) {
-					case FlatClientProperties.SCROLL_BAR_SHOW_BUTTONS:
-						JScrollBar vsb = scrollpane.getVerticalScrollBar();
-						JScrollBar hsb = scrollpane.getHorizontalScrollBar();
-						if( vsb != null ) {
-							vsb.revalidate();
-							vsb.repaint();
-						}
-						if( hsb != null ) {
-							hsb.revalidate();
-							hsb.repaint();
-						}
-						break;
-
-					case ScrollPaneConstants.LOWER_LEFT_CORNER:
-					case ScrollPaneConstants.LOWER_RIGHT_CORNER:
-					case ScrollPaneConstants.UPPER_LEFT_CORNER:
-					case ScrollPaneConstants.UPPER_RIGHT_CORNER:
-						// remove border from buttons added to corners
-						Object corner = e.getNewValue();
-						if( corner instanceof JButton &&
-							((JButton)corner).getBorder() instanceof FlatButtonBorder &&
-							scrollpane.getViewport() != null &&
-							scrollpane.getViewport().getView() instanceof JTable )
-						{
-							((JButton)corner).setBorder( BorderFactory.createEmptyBorder() );
-							((JButton)corner).setFocusable( false );
-						}
+			switch( e.getPropertyName() ) {
+				case FlatClientProperties.SCROLL_BAR_SHOW_BUTTONS:
+					JScrollBar vsb = scrollpane.getVerticalScrollBar();
+					JScrollBar hsb = scrollpane.getHorizontalScrollBar();
+					if( vsb != null ) {
+						vsb.revalidate();
+						vsb.repaint();
+					}
+					if( hsb != null ) {
+						hsb.revalidate();
+						hsb.repaint();
+					}
 					break;
-				}
+
+				case ScrollPaneConstants.LOWER_LEFT_CORNER:
+				case ScrollPaneConstants.LOWER_RIGHT_CORNER:
+				case ScrollPaneConstants.UPPER_LEFT_CORNER:
+				case ScrollPaneConstants.UPPER_RIGHT_CORNER:
+					// remove border from buttons added to corners
+					Object corner = e.getNewValue();
+					if( corner instanceof JButton &&
+						((JButton)corner).getBorder() instanceof FlatButtonBorder &&
+						scrollpane.getViewport() != null &&
+						scrollpane.getViewport().getView() instanceof JTable )
+					{
+						((JButton)corner).setBorder( BorderFactory.createEmptyBorder() );
+						((JButton)corner).setFocusable( false );
+					}
+				break;
 			}
 		};
 	}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTreeUI.java

@@ -25,7 +25,6 @@ import java.awt.Insets;
 import java.awt.Rectangle;
 import java.awt.event.MouseEvent;
 import java.awt.event.MouseListener;
-import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 import javax.swing.CellRendererPane;
 import javax.swing.Icon;
@@ -193,40 +192,38 @@ public class FlatTreeUI
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener() {
-		return new BasicTreeUI.PropertyChangeHandler() {
-			@Override
-			public void propertyChange( PropertyChangeEvent e ) {
-				super.propertyChange( e );
+		PropertyChangeListener superListener = super.createPropertyChangeListener();
+		return e -> {
+			superListener.propertyChange( e );
 
-				if( e.getSource() == tree ) {
-					switch( e.getPropertyName() ) {
-						case TREE_WIDE_SELECTION:
-						case TREE_PAINT_SELECTION:
-							tree.repaint();
-							break;
+			if( e.getSource() == tree ) {
+				switch( e.getPropertyName() ) {
+					case TREE_WIDE_SELECTION:
+					case TREE_PAINT_SELECTION:
+						tree.repaint();
+						break;
 
-						case "dropLocation":
-							if( isWideSelection() ) {
-								JTree.DropLocation oldValue = (JTree.DropLocation) e.getOldValue();
-								repaintWideDropLocation( oldValue );
-								repaintWideDropLocation( tree.getDropLocation() );
-							}
-							break;
-					}
+					case "dropLocation":
+						if( isWideSelection() ) {
+							JTree.DropLocation oldValue = (JTree.DropLocation) e.getOldValue();
+							repaintWideDropLocation( oldValue );
+							repaintWideDropLocation( tree.getDropLocation() );
+						}
+						break;
 				}
 			}
-
-			private void repaintWideDropLocation(JTree.DropLocation loc) {
-				if( loc == null || isDropLine( loc ) )
-					return;
-
-				Rectangle r = tree.getPathBounds( loc.getPath() );
-				if( r != null )
-					tree.repaint( 0, r.y, tree.getWidth(), r.height );
-			}
 		};
 	}
 
+	private void repaintWideDropLocation(JTree.DropLocation loc) {
+		if( loc == null || isDropLine( loc ) )
+			return;
+
+		Rectangle r = tree.getPathBounds( loc.getPath() );
+		if( r != null )
+			tree.repaint( 0, r.y, tree.getWidth(), r.height );
+	}
+
 	/**
 	 * Same as super.paintRow(), but supports wide selection and uses
 	 * inactive selection background/foreground if tree is not focused.

flatlaf-jide-oss/src/main/java/com/formdev/flatlaf/jideoss/ui/FlatJideTabbedPaneUI.java

@@ -32,7 +32,6 @@ import java.awt.event.MouseListener;
 import java.awt.event.MouseMotionListener;
 import java.awt.geom.Path2D;
 import java.awt.geom.Rectangle2D;
-import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 import javax.swing.JComponent;
 import javax.swing.UIManager;
@@ -111,19 +110,17 @@ public class FlatJideTabbedPaneUI
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener() {
-		return new PropertyChangeHandler() {
-			@Override
-			public void propertyChange( PropertyChangeEvent e ) {
-				super.propertyChange( e );
+		PropertyChangeListener superListener = super.createPropertyChangeListener();
+		return e -> {
+			superListener.propertyChange( e );
 
-				String propertyName = e.getPropertyName();
-				if( JideTabbedPane.PROPERTY_SELECTED_INDEX.equals( propertyName ) ) {
-					repaintTab( (Integer) e.getOldValue() );
-					repaintTab( (Integer) e.getNewValue() );
-				} else if( FlatClientProperties.TABBED_PANE_HAS_FULL_BORDER.equals( propertyName ) ) {
-					_tabPane.revalidate();
-					_tabPane.repaint();
-				}
+			String propertyName = e.getPropertyName();
+			if( JideTabbedPane.PROPERTY_SELECTED_INDEX.equals( propertyName ) ) {
+				repaintTab( (Integer) e.getOldValue() );
+				repaintTab( (Integer) e.getNewValue() );
+			} else if( FlatClientProperties.TABBED_PANE_HAS_FULL_BORDER.equals( propertyName ) ) {
+				_tabPane.revalidate();
+				_tabPane.repaint();
 			}
 		};
 	}