Fix language fallback'ing

src/main/java/emu/grasscutter/utils/Language.java

@@ -48,11 +48,13 @@ public final class Language {
 
         try {
             InputStream file = Grasscutter.class.getResourceAsStream("/languages/" + fileName);
-            if(file == null) {
+            String translationContents = Utils.readFromInputStream(file);
+            if(translationContents.equals("empty")) {
                 file = Grasscutter.class.getResourceAsStream("/languages/" + fallback);
+                translationContents = Utils.readFromInputStream(file);
             }
             
-            languageData = Grasscutter.getGsonFactory().fromJson(Utils.readFromInputStream(file), JsonObject.class);
+            languageData = Grasscutter.getGsonFactory().fromJson(translationContents, JsonObject.class);
         } catch (Exception exception) {
             Grasscutter.getLogger().warn("Failed to load language file: " + fileName, exception);
         }

src/main/java/emu/grasscutter/utils/Utils.java

@@ -18,6 +18,8 @@ import io.netty.buffer.Unpooled;
 
 import org.slf4j.Logger;
 
+import javax.annotation.Nullable;
+
 import static emu.grasscutter.utils.Language.translate;
 
 @SuppressWarnings({"UnusedReturnValue", "BooleanMethodIsAlwaysInverted"})
@@ -253,7 +255,9 @@ public final class Utils {
 	 * @param stream The input stream.
 	 * @return The string.
 	 */
-	public static String readFromInputStream(InputStream stream) {
+	public static String readFromInputStream(@Nullable InputStream stream) {
+		if(stream == null) return "empty";
+		
 		StringBuilder stringBuilder = new StringBuilder();
 		try (BufferedReader reader = new BufferedReader(new InputStreamReader(stream, StandardCharsets.UTF_8))) {
 			String line; while ((line = reader.readLine()) != null) {
@@ -261,6 +265,8 @@ public final class Utils {
 			} stream.close();
 		} catch (IOException e) {
 			Grasscutter.getLogger().warn("Failed to read from input stream.");
+		} catch (NullPointerException ignored) {
+			return "empty";
 		} return stringBuilder.toString();
 	}