core: minor code cleanup:

- add final where possible
- removed "public" from interface methods
- simplified conditional expressions
- removed unnecessary unboxing
- removed unused assignements
- removed redundant casts

(used IntelliJ IDEA 2021.3 inspections)

flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java

@@ -605,7 +605,7 @@ public abstract class FlatLaf
 			uiFont = ((ActiveFont)defaultFont).derive( baseFont, fontSize -> {
 				return Math.round( fontSize * UIScale.computeFontScaleFactor( baseFont ) );
 			} );
-		};
+		}
 
 		// increase font size if system property "flatlaf.uiScale" is set
 		uiFont = UIScale.applyCustomScaleFactor( uiFont );

flatlaf-core/src/main/java/com/formdev/flatlaf/IntelliJTheme.java

@@ -534,12 +534,12 @@ public class IntelliJTheme
 	}
 
 	/** Rename UI default keys (key --> value). */
-	private static Map<String, String> uiKeyMapping = new HashMap<>();
+	private static final Map<String, String> uiKeyMapping = new HashMap<>();
 	/** Copy UI default keys (value --> key). */
-	private static Map<String, String> uiKeyCopying = new HashMap<>();
+	private static final Map<String, String> uiKeyCopying = new HashMap<>();
-	private static Map<String, String> uiKeyInverseMapping = new HashMap<>();
+	private static final Map<String, String> uiKeyInverseMapping = new HashMap<>();
-	private static Map<String, String> checkboxKeyMapping = new HashMap<>();
+	private static final Map<String, String> checkboxKeyMapping = new HashMap<>();
-	private static Map<String, String> checkboxDuplicateColors = new HashMap<>();
+	private static final Map<String, String> checkboxDuplicateColors = new HashMap<>();
 
 	static {
 		// ComboBox

flatlaf-core/src/main/java/com/formdev/flatlaf/LinuxFontPolicy.java

@@ -170,7 +170,7 @@ class LinuxFontPolicy
 
 		Object value = Toolkit.getDefaultToolkit().getDesktopProperty( "gnome.Xft/DPI" );
 		if( value instanceof Integer ) {
-			int dpi = ((Integer)value).intValue() / 1024;
+			int dpi = (Integer) value / 1024;
 			if( dpi == -1 )
 				dpi = 96;
 			if( dpi < 50 )
@@ -278,7 +278,7 @@ class LinuxFontPolicy
 		// read config file
 		ArrayList<String> lines = new ArrayList<>( 200 );
 		try( BufferedReader reader = new BufferedReader( new FileReader( file ) ) ) {
-			String line = null;
+			String line;
 			while( (line = reader.readLine()) != null )
 				lines.add( line );
 		} catch( IOException ex ) {

flatlaf-core/src/main/java/com/formdev/flatlaf/UIDefaultsLoader.java

@@ -350,7 +350,7 @@ class UIDefaultsLoader
 	enum ValueType { UNKNOWN, STRING, BOOLEAN, CHARACTER, INTEGER, INTEGERORFLOAT, FLOAT, BORDER, ICON, INSETS, DIMENSION, COLOR, FONT,
 		SCALEDINTEGER, SCALEDFLOAT, SCALEDINSETS, SCALEDDIMENSION, INSTANCE, CLASS, GRAYFILTER, NULL, LAZY }
 
-	private static ValueType[] tempResultValueType = new ValueType[1];
+	private static final ValueType[] tempResultValueType = new ValueType[1];
 	private static Map<Class<?>, ValueType> javaValueTypes;
 	private static Map<String, ValueType> knownValueTypes;
 
@@ -1209,7 +1209,7 @@ class UIDefaultsLoader
 		}
 
 		Integer integer = parseInteger( value, true );
-		if( integer.intValue() < min || integer.intValue() > max )
+		if( integer < min || integer > max )
 			throw new NumberFormatException( "integer '" + value + "' out of range (" + min + '-' + max + ')' );
 		return integer;
 	}
@@ -1250,28 +1250,28 @@ class UIDefaultsLoader
 
 	private static ActiveValue parseScaledInteger( String value ) {
 		int val = parseInteger( value, true );
-		return (ActiveValue) t -> {
+		return t -> {
 			return UIScale.scale( val );
 		};
 	}
 
 	private static ActiveValue parseScaledFloat( String value ) {
 		float val = parseFloat( value, true );
-		return (ActiveValue) t -> {
+		return t -> {
 			return UIScale.scale( val );
 		};
 	}
 
 	private static ActiveValue parseScaledInsets( String value ) {
 		Insets insets = parseInsets( value );
-		return (ActiveValue) t -> {
+		return t -> {
 			return UIScale.scale( insets );
 		};
 	}
 
 	private static ActiveValue parseScaledDimension( String value ) {
 		Dimension dimension = parseDimension( value );
-		return (ActiveValue) t -> {
+		return t -> {
 			return UIScale.scale( dimension );
 		};
 	}

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

@@ -700,7 +700,7 @@ public class FlatComboBoxUI
 				return true;
 
 			Component editorComponent = comboBox.getEditor().getEditorComponent();
-			return (editorComponent != null) ? FlatUIUtils.isPermanentFocusOwner( editorComponent ) : false;
+			return editorComponent != null && FlatUIUtils.isPermanentFocusOwner( editorComponent );
 		} else
 			return FlatUIUtils.isPermanentFocusOwner( comboBox );
 	}

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

@@ -199,7 +199,7 @@ public class FlatRadioButtonUI
 		return infos;
 	}
 
-	private static Insets tempInsets = new Insets( 0, 0, 0, 0 );
+	private static final Insets tempInsets = new Insets( 0, 0, 0, 0 );
 
 	@Override
 	public Dimension getPreferredSize( JComponent c ) {

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

@@ -510,7 +510,7 @@ public class FlatRootPaneUI
 				return;
 
 			Container parent = c.getParent();
-			boolean active = parent instanceof Window ? ((Window)parent).isActive() : false;
+			boolean active = parent instanceof Window && ((Window)parent).isActive();
 
 			g.setColor( FlatUIUtils.deriveColor( active ? activeBorderColor : inactiveBorderColor, baseBorderColor ) );
 			HiDPIUtils.paintAtScale1x( (Graphics2D) g, x, y, width, height, this::paintImpl );
@@ -522,9 +522,7 @@ public class FlatRootPaneUI
 
 		protected boolean isWindowMaximized( Component c ) {
 			Container parent = c.getParent();
-			return parent instanceof Frame
+			return parent instanceof Frame && (((Frame)parent).getExtendedState() & Frame.MAXIMIZED_BOTH) != 0;
-				? (((Frame)parent).getExtendedState() & Frame.MAXIMIZED_BOTH) != 0
-				: false;
 		}
 	}
 

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

@@ -293,9 +293,7 @@ public class FlatSpinnerUI
 			return true;
 
 		JTextField textField = getEditorTextField( spinner.getEditor() );
-		return (textField != null)
+		return textField != null && FlatUIUtils.isPermanentFocusOwner( textField );
-			? FlatUIUtils.isPermanentFocusOwner( textField )
-			: false;
 	}
 
 	protected Color getBackground( boolean enabled ) {

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

@@ -650,7 +650,7 @@ public class FlatTabbedPaneUI
 				case "tabIconPlacement": value = parseTabIconPlacement( (String) value ); break;
 			}
 		} else {
-			Object oldValue = null;
+			Object oldValue;
 			switch( key ) {
 				// BasicTabbedPaneUI
 				case "tabInsets": oldValue = tabInsets; tabInsets = (Insets) value; return oldValue;
@@ -2412,7 +2412,7 @@ public class FlatTabbedPaneUI
 			if( tabPane == null || tabViewport == null )
 				return;
 
-			if( !scrolled || tabViewport == null )
+			if( !scrolled )
 				return;
 			scrolled = false;
 
@@ -2525,9 +2525,7 @@ public class FlatTabbedPaneUI
 			setRolloverTab( tabIndex );
 
 			// check whether mouse hit tab close area
-			boolean hitClose = isTabClosable( tabIndex )
+			boolean hitClose = isTabClosable( tabIndex ) && getTabCloseHitArea( tabIndex ).contains( x, y );
-				? getTabCloseHitArea( tabIndex ).contains( x, y )
-				: false;
 			if( e.getID() == MouseEvent.MOUSE_PRESSED )
 				pressedTabIndex = hitClose ? tabIndex : -1;
 			setRolloverTabClose( hitClose );
@@ -2550,8 +2548,7 @@ public class FlatTabbedPaneUI
 			if( tabIndex == lastTipTabIndex )
 				return; // closeTip already set
 
-			if( tabIndex != lastTipTabIndex )
+			restoreTabToolTip();
-				restoreTabToolTip();
 
 			lastTipTabIndex = tabIndex;
 			lastTip = tabPane.getToolTipTextAt( lastTipTabIndex );

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

@@ -883,9 +883,7 @@ debug*/
 		}
 
 		protected boolean isWindowMaximized( Component c ) {
-			return window instanceof Frame
+			return window instanceof Frame && (((Frame) window).getExtendedState() & Frame.MAXIMIZED_BOTH) != 0;
-				? (((Frame)window).getExtendedState() & Frame.MAXIMIZED_BOTH) != 0
-				: false;
 		}
 	}
 

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

@@ -164,11 +164,7 @@ public class FlatToggleButtonUI
 	@Override
 	public Map<String, Class<?>> getStyleableInfos( JComponent c ) {
 		Map<String, Class<?>> infos = super.getStyleableInfos( c );
-		Iterator<String> it = infos.keySet().iterator();
+		infos.keySet().removeIf( s -> s.startsWith( "help." ) );
-		while( it.hasNext() ) {
-			if( it.next().startsWith( "help." ) )
-				it.remove();
-		}
 		return infos;
 	}
 

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

@@ -71,7 +71,7 @@ public class FlatUIUtils
 	public static final boolean MAC_USE_QUARTZ = Boolean.getBoolean( "apple.awt.graphics.UseQuartz" );
 
 	private static boolean useSharedUIs = true;
-	private static WeakHashMap<LookAndFeel, IdentityHashMap<Object, ComponentUI>> sharedUIinstances = new WeakHashMap<>();
+	private static final WeakHashMap<LookAndFeel, IdentityHashMap<Object, ComponentUI>> sharedUIinstances = new WeakHashMap<>();
 
 	public static Rectangle addInsets( Rectangle r, Insets insets ) {
 		return new Rectangle(

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

@@ -284,7 +284,7 @@ public class JBRCustomDecorations
 		@Override
 		public void paintBorder( Component c, Graphics g, int x, int y, int width, int height ) {
 			Window window = SwingUtilities.windowForComponent( c );
-			boolean active = (window != null) ? window.isActive() : false;
+			boolean active = window != null && window.isActive();
 
 			// paint top border
 			//  - in light themes

flatlaf-core/src/main/java/com/formdev/flatlaf/util/AnimatedIcon.java

@@ -68,7 +68,7 @@ public interface AnimatedIcon
 	extends Icon
 {
 	@Override
-	public default void paintIcon( Component c, Graphics g, int x, int y ) {
+	default void paintIcon( Component c, Graphics g, int x, int y ) {
 		AnimationSupport.paintIcon( this, c, g, x, y );
 	}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/util/HSLColor.java

@@ -291,7 +291,7 @@ public class HSLColor
 
 		//  Calculate the Saturation
 
-		float s = 0;
+		float s;
 
 		if (max == min)
 			s = 0;
@@ -386,7 +386,7 @@ public class HSLColor
 		s /= 100f;
 		l /= 100f;
 
-		float q = 0;
+		float q;
 
 		if (l < 0.5)
 			q = l * (1 + s);

flatlaf-core/src/main/java/com/formdev/flatlaf/util/HiDPIUtils.java

@@ -31,7 +31,7 @@ import com.formdev.flatlaf.FlatSystemProperties;
 public class HiDPIUtils
 {
 	public interface Painter {
-		public void paint( Graphics2D g, int x, int y, int width, int height, double scaleFactor );
+		void paint( Graphics2D g, int x, int y, int width, int height, double scaleFactor );
 	}
 
 	public static void paintAtScale1x( Graphics2D g, JComponent c, Painter painter ) {

flatlaf-core/src/main/java/com/formdev/flatlaf/util/JavaCompatibility.java

@@ -89,7 +89,7 @@ public class JavaCompatibility
 					getClippedStringMethod = cls.getMethod( SystemInfo.isJava_9_orLater
 							? "getClippedString"
 							: "clipStringIfNecessary",
-						new Class[] { JComponent.class, FontMetrics.class, String.class, int.class } );
+						JComponent.class, FontMetrics.class, String.class, int.class );
 				} catch( Exception ex ) {
 					LoggingFacade.INSTANCE.logSevere( null, ex );
 					throw new RuntimeException( ex );