diff --git a/jadx-gui/src/main/java/jadx/gui/ui/MainWindow.java b/jadx-gui/src/main/java/jadx/gui/ui/MainWindow.java
index 9abcf03123486c283131904209643854def5a664..5b8bf67c8e0951f95edd8d8327438cb24d17f8e2 100644
--- a/jadx-gui/src/main/java/jadx/gui/ui/MainWindow.java
+++ b/jadx-gui/src/main/java/jadx/gui/ui/MainWindow.java
@@ -340,7 +340,7 @@ public class MainWindow extends JFrame {
 				openFile();
 			}
 		};
-		openAction.putValue(Action.SHORT_DESCRIPTION, NLS.str("file.open"));
+		openAction.putValue(Action.SHORT_DESCRIPTION, NLS.str("file.open_action"));
 		openAction.putValue(Action.ACCELERATOR_KEY, getKeyStroke(KeyEvent.VK_O, KeyEvent.CTRL_DOWN_MASK));
 
 		Action saveAllAction = new AbstractAction(NLS.str("file.save_all"), ICON_SAVE_ALL) {
diff --git a/jadx-gui/src/main/java/jadx/gui/utils/NLS.java b/jadx-gui/src/main/java/jadx/gui/utils/NLS.java
index 3247bf01b455a6cce1030b971e33f846c9de3241..4e30a67278a0d2e40140f693c80940167d35c4b1 100644
--- a/jadx-gui/src/main/java/jadx/gui/utils/NLS.java
+++ b/jadx-gui/src/main/java/jadx/gui/utils/NLS.java
@@ -1,102 +1,99 @@
-package jadx.gui.utils;
-
-import java.nio.charset.Charset;
-import java.util.HashMap;
-import java.util.Locale;
-import java.util.Map;
-import java.util.ResourceBundle;
-import java.util.Vector;
-
-import org.jetbrains.annotations.NotNull;
-
-public class NLS {
-	private static final Charset JAVA_CHARSET = Charset.forName("ISO-8859-1");
-	private static final Charset UTF8_CHARSET = Charset.forName("UTF-8");
-
-	private static Vector<LangLocale> i18nLocales = new Vector<>();
-
-	private static Map<LangLocale, Map<String, String>> i18nMessagesMap = new HashMap<>();
-
-	// Use these two fields to avoid invoking Map.get() method twice.
-	private static Map<String, String> localizedMessagesMap;
-	private static Map<String, String> fallbackMessagesMap;
-
-	private static LangLocale currentLocale;
-	private static LangLocale localLocale;
-
-	static {
-		localLocale = new LangLocale(Locale.getDefault());
-
-		i18nLocales.add(new LangLocale("en", "US")); // As default language
-		i18nLocales.add(new LangLocale("zh", "CN"));
-		i18nLocales.add(new LangLocale("es", "ES"));
-
-		i18nLocales.forEach(NLS::load);
-
-		LangLocale defLang = i18nLocales.get(0);
-		fallbackMessagesMap = i18nMessagesMap.get(defLang);
-		localizedMessagesMap = i18nMessagesMap.get(defLang);
-	}
-
-	private NLS() {
-	}
-
-	private static void load(LangLocale locale) {
-		ResourceBundle bundle = ResourceBundle.getBundle("i18n/Messages", locale.get());
-		Map<String, String> resMap = new HashMap<>();
-		for (String key : bundle.keySet()) {
-			String str = bundle.getString(key);
-			resMap.put(key, convertCharset(str));
-		}
-		i18nMessagesMap.put(locale, resMap);
-	}
-
-	@NotNull
-	private static String convertCharset(String str) {
-		return new String(str.getBytes(JAVA_CHARSET), UTF8_CHARSET);
-	}
-
-	public static String str(String key) {
-		String str = localizedMessagesMap.get(key);
-		if (str != null) {
-			return str;
-		}
-		return fallbackMessagesMap.get(key); // definitely exists
-	}
-
-	public static String str(String key, LangLocale locale) {
-		Map<String, String> strings = i18nMessagesMap.get(locale);
-		if (strings != null) {
-			String str = strings.get(key);
-			if (str != null) {
-				return str;
-			}
-		}
-		return fallbackMessagesMap.get(key); // definitely exists
-	}
-
-	public static void setLocale(LangLocale locale) {
-		if (i18nMessagesMap.containsKey(locale)) {
-			currentLocale = locale;
-		} else {
-			currentLocale = i18nLocales.get(0);
-		}
-		localizedMessagesMap = i18nMessagesMap.get(currentLocale);
-	}
-
-	public static Vector<LangLocale> getI18nLocales() {
-		return i18nLocales;
-	}
-
-	public static LangLocale currentLocale() {
-		return currentLocale;
-	}
-
-	public static LangLocale defaultLocale() {
-		if (i18nMessagesMap.containsKey(localLocale)) {
-			return localLocale;
-		}
-		// fallback to english if unsupported
-		return i18nLocales.get(0);
-	}
-}
+package jadx.gui.utils;
+
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.net.URL;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.*;
+
+import org.jetbrains.annotations.NotNull;
+
+public class NLS {
+
+	private static Vector<LangLocale> i18nLocales = new Vector<>();
+
+	private static Map<LangLocale, ResourceBundle> i18nMessagesMap = new HashMap<>();
+
+	// Use these two fields to avoid invoking Map.get() method twice.
+	private static ResourceBundle localizedMessagesMap;
+	private static ResourceBundle fallbackMessagesMap;
+
+	private static LangLocale currentLocale;
+	private static LangLocale localLocale;
+
+	static {
+		localLocale = new LangLocale(Locale.getDefault());
+
+		i18nLocales.add(new LangLocale("en", "US")); // As default language
+		i18nLocales.add(new LangLocale("zh", "CN"));
+		i18nLocales.add(new LangLocale("es", "ES"));
+
+		i18nLocales.forEach(NLS::load);
+
+		LangLocale defLang = i18nLocales.get(0);
+		fallbackMessagesMap = i18nMessagesMap.get(defLang);
+		localizedMessagesMap = i18nMessagesMap.get(defLang);
+	}
+
+	private NLS() {
+	}
+
+	private static void load(LangLocale locale) {
+		ResourceBundle bundle;
+		ClassLoader classLoader = ClassLoader.getSystemClassLoader();
+		String resName = String.format("i18n/Messages_%s.properties", locale.get());
+		URL bundleUrl = classLoader.getResource(resName);
+		try (Reader reader = new InputStreamReader(bundleUrl.openStream(), StandardCharsets.UTF_8)) {
+			bundle = new PropertyResourceBundle(reader);
+		} catch (IOException e) {
+			throw new RuntimeException("Failed to load " + resName, e);
+		}
+		i18nMessagesMap.put(locale, bundle);
+	}
+
+	public static String str(String key) {
+		try {
+			return localizedMessagesMap.getString(key);
+		} catch (MissingResourceException e) {
+			return fallbackMessagesMap.getString(key); // definitely exists
+		}
+	}
+
+	public static String str(String key, LangLocale locale) {
+		ResourceBundle bundle = i18nMessagesMap.get(locale);
+		if (bundle != null) {
+			try {
+				return bundle.getString(key);
+			} catch (MissingResourceException e) {
+			}
+		}
+		return fallbackMessagesMap.getString(key); // definitely exists
+	}
+
+	public static void setLocale(LangLocale locale) {
+		if (i18nMessagesMap.containsKey(locale)) {
+			currentLocale = locale;
+		} else {
+			currentLocale = i18nLocales.get(0);
+		}
+		localizedMessagesMap = i18nMessagesMap.get(currentLocale);
+	}
+
+	public static Vector<LangLocale> getI18nLocales() {
+		return i18nLocales;
+	}
+
+	public static LangLocale currentLocale() {
+		return currentLocale;
+	}
+
+	public static LangLocale defaultLocale() {
+		if (i18nMessagesMap.containsKey(localLocale)) {
+			return localLocale;
+		}
+		// fallback to english if unsupported
+		return i18nLocales.get(0);
+	}
+}