diff --git a/pkgs/jnigen/example/pdfbox_plugin/example/README.md b/pkgs/jnigen/example/pdfbox_plugin/example/README.md
index 0f471bec6d..25ccda4406 100644
--- a/pkgs/jnigen/example/pdfbox_plugin/example/README.md
+++ b/pkgs/jnigen/example/pdfbox_plugin/example/README.md
@@ -10,6 +10,7 @@ On a Linux machine, following commands can be used to run the example applicatio
 cd .. ## From this folder
 dart run jnigen --config jnigen.yaml ## Downloads PDFBox JARs and generates bindings.
 cd example/
+dart run jni:setup
 flutter run --release ## Opens the files list from home directory
 ```
 
diff --git a/pkgs/jnigen/example/pdfbox_plugin/example/lib/main.dart b/pkgs/jnigen/example/pdfbox_plugin/example/lib/main.dart
index a70d514b4e..b2363cf300 100644
--- a/pkgs/jnigen/example/pdfbox_plugin/example/lib/main.dart
+++ b/pkgs/jnigen/example/pdfbox_plugin/example/lib/main.dart
@@ -67,8 +67,6 @@ class PDFInfoAppState extends State<PDFInfoApp> {
       final isDir = (await item.stat()).type == FileSystemEntityType.directory;
       if (item.path.endsWith('.pdf') && !isDir) {
         pdfs.add(item.path);
-      } else if (isDir) {
-        dirs.add(item.path);
       }
     }
     setState(() {
@@ -158,9 +156,10 @@ class PDFFileInfo {
     // Since java.io is not directly available, use package:jni API to
     // create a java.io.File object.
     final fileClass = JClass.forName("java/io/File");
-    final inputFile = fileClass
-        .constructorId("(Ljava/lang/String;)V")
-        .call(fileClass, JObject.type, [filename]);
+    final fileConstructor = fileClass.constructorId("(Ljava/lang/String;)V");
+    final inputFile = fileConstructor(
+        fileClass, JObject.type, [JString.fromString(filename)]);
+
     // Static method call PDDocument.load -> PDDocument
     final pdf = PDDocument.load(inputFile)!;
     // Instance method call getNumberOfPages() -> int