Use JDK 9 MultiResolutionImage

source/net/filebot/Main.java

@@ -203,14 +203,14 @@ public class Main {
 			MacAppUtilities.initializeApplication(FileBotMenuBar.createHelp(), files -> SwingEventBus.getInstance().post(new FileTransferable(files)));
 		} else if (isUbuntuApp()) {
 			// Ubuntu/Debian specific configuration
-			frame.setIconImages(ResourceManager.getApplicationIcons());
+			frame.setIconImages(ResourceManager.getApplicationIconImages());
 		} else if (isWindowsApp()) {
 			// Windows specific configuration
 			WinAppUtilities.initializeApplication();
-			frame.setIconImages(ResourceManager.getApplicationIcons());
+			frame.setIconImages(ResourceManager.getApplicationIconImages());
 		} else {
 			// generic Linux/FreeBSD/Solaris configuration
-			frame.setIconImages(ResourceManager.getApplicationIcons());
+			frame.setIconImages(ResourceManager.getApplicationIconImages());
 		}
 
 		// start application

source/net/filebot/ResourceManager.java

@@ -1,97 +1,85 @@
 package net.filebot;
 
+import static java.util.Arrays.*;
+import static java.util.Collections.*;
 import static java.util.stream.Collectors.*;
 
 import java.awt.Image;
 import java.awt.Toolkit;
+import java.awt.image.BaseMultiResolutionImage;
 import java.net.URL;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
+import java.util.Objects;
 import java.util.stream.Stream;
 
+import javax.imageio.ImageIO;
 import javax.swing.Icon;
 import javax.swing.ImageIcon;
 
-import net.filebot.util.WeakValueHashMap;
-
 public final class ResourceManager {
 
-	private static final WeakValueHashMap<String, Icon> cache = new WeakValueHashMap<String, Icon>(256);
+	private static final Map<String, Icon> cache = synchronizedMap(new HashMap<String, Icon>(256));
 
-	public static Icon getIcon(String name) {
-		return getIcon(name, null);
+	public static Icon getIcon(String... name) {
+		return getIcon(asList(name));
 	}
 
-	public static Icon getIcon(String name, String def) {
-		Icon icon = null;
-
-		// try cache
-		synchronized (cache) {
-			icon = cache.get(name);
-			if (icon != null) {
-				return icon;
+	private static Icon getIcon(List<String> icons) {
+		return cache.computeIfAbsent(icons.get(0), i -> {
+			// load image
+			URL[] resource = getMultiResolutionImageResource(i);
+			if (resource.length > 0) {
+				return new ImageIcon(getMultiResolutionImage(resource));
+			}
+
+			// try next image
+			if (icons.size() > 0) {
+				return getIcon(icons.subList(1, icons.size()));
 			}
-		}
 
-		URL resource = getImageResource(name, def);
-		if (resource == null) {
 			return null;
-		}
-
-		Image image = getImage(resource);
-		icon = new ImageIcon(image);
-
-		// update cache
-		synchronized (cache) {
-			cache.put(name, icon);
-		}
-
-		return icon;
+		});
 	}
 
 	public static Stream<URL> getApplicationIconResources() {
 		return Stream.of("window.icon.large", "window.icon.medium", "window.icon.small").map(ResourceManager::getImageResource);
 	}
 
-	public static List<Image> getApplicationIcons() {
-		return getApplicationIconResources().map(ResourceManager::getImage).collect(toList());
+	public static List<Image> getApplicationIconImages() {
+		return getApplicationIconResources().map(ResourceManager::getToolkitImage).collect(toList());
 	}
 
 	public static Icon getFlagIcon(String languageCode) {
 		return getIcon("flags/" + languageCode);
 	}
 
-	public static Image getImage(String name) {
-		return getImage(getImageResource(name));
-	}
-
-	private static Image getImage(URL resource) {
+	private static Image getToolkitImage(URL resource) {
 		// load sun.awt.image.ToolkitImage or sun.awt.image.MultiResolutionToolkitImage (via @2x convention)
 		return Toolkit.getDefaultToolkit().getImage(resource);
 	}
 
-	/**
-	 * Get the URL of an image resource in this jar. Image must be located in <code>resources/</code> and the file type is assumed to be png.
-	 *
-	 * @param name
-	 *            simple name of the resource (without extension)
-	 * @return URL of the resource or null if resource does not exist
-	 */
+	private static Image getMultiResolutionImage(URL[] resource) {
+		try {
+			Image[] image = new Image[resource.length];
+			for (int i = 0; i < image.length; i++) {
+				image[i] = ImageIO.read(resource[i]);
+			}
+			return new BaseMultiResolutionImage(image);
+		} catch (Exception e) {
+			throw new RuntimeException(e);
+		}
+	}
+
+	private static URL[] getMultiResolutionImageResource(String name) {
+		return Stream.of(name, name + "@2x").map(ResourceManager::getImageResource).filter(Objects::nonNull).toArray(URL[]::new);
+	}
+
 	private static URL getImageResource(String name) {
 		return ResourceManager.class.getResource("resources/" + name + ".png");
 	}
 
-	private static URL getImageResource(String name, String def) {
-		URL resource = getImageResource(name);
-
-		if (resource == null)
-			resource = getImageResource(def);
-
-		return resource;
-	}
-
-	/**
-	 * Dummy constructor to prevent instantiation.
-	 */
 	private ResourceManager() {
 		throw new UnsupportedOperationException();
 	}