diff --git a/.github/workflows/CI.yaml b/.github/workflows/CI.yaml
index 958d7cd..bbbc951 100644
--- a/.github/workflows/CI.yaml
+++ b/.github/workflows/CI.yaml
@@ -3,7 +3,7 @@ name: CI
 on: [push, pull_request]
 
 jobs:
-  jvm:
+  kotlin-build:
     runs-on: ubuntu-latest
 
     steps:
@@ -48,7 +48,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.repository == 'SimonScholz/qr-code-with-logo' && github.ref == 'refs/heads/main'
     needs:
-      - jvm
+      - kotlin-build
       - java-sample-different-jdks
     steps:
       - uses: actions/checkout@v4
diff --git a/java-sample/build.gradle.kts b/java-sample/build.gradle.kts
index ad07c79..c1c569b 100644
--- a/java-sample/build.gradle.kts
+++ b/java-sample/build.gradle.kts
@@ -14,6 +14,9 @@ repositories {
 
 dependencies {
     implementation("io.github.simonscholz:qr-code-with-logo:0.1.0-SNAPSHOT")
+
+    testImplementation("org.junit.jupiter:junit-jupiter-engine:5.10.0")
+    testImplementation("org.junit.jupiter:junit-jupiter-params:5.10.0")
 }
 
 tasks.test {
diff --git a/java-sample/src/main/java/io/github/simonscholz/Main.java b/java-sample/src/main/java/io/github/simonscholz/Main.java
index 0b8992c..faba3a9 100644
--- a/java-sample/src/main/java/io/github/simonscholz/Main.java
+++ b/java-sample/src/main/java/io/github/simonscholz/Main.java
@@ -7,7 +7,7 @@
 import io.github.simonscholz.qrcode.QrPositionalSquaresConfig;
 
 import javax.imageio.ImageIO;
-import java.awt.Color;
+import java.awt.*;
 import java.awt.image.BufferedImage;
 import java.io.File;
 import java.io.IOException;
@@ -31,9 +31,12 @@ public static void main(final String[] args) throws IOException {
         final QrCodeApi qrCodeApi = QrCodeFactory.createQrCodeApi();
         final Path path = Paths.get(System.getProperty("user.home"), "qr-code-samples");
         Files.createDirectories(path);
-        final var qrCodeDir = path.toAbsolutePath()
-                                  .toString();
+        final String qrCodeDir = path.toAbsolutePath().toString();
 
+        generateSamples(qrCodeApi, qrCodeDir);
+    }
+
+    static void generateSamples(QrCodeApi qrCodeApi, String qrCodeDir) throws IOException {
         createDefaultQrCode(qrCodeApi, qrCodeDir);
 
         final URL resource = Main.class.getClassLoader()
@@ -60,7 +63,7 @@ public static void main(final String[] args) throws IOException {
     }
 
     private static void createDefaultQrCode(final QrCodeApi qrCodeApi, final String qrCodeDir) throws IOException {
-        final var qrCode = qrCodeApi.createQrCodeImage(new QrCodeConfig("https://simonscholz.github.io/", DEFAULT_IMG_SIZE));
+        final BufferedImage qrCode = qrCodeApi.createQrCodeImage(new QrCodeConfig("https://simonscholz.github.io/", DEFAULT_IMG_SIZE));
         ImageIO.write(qrCode, "png", new File(qrCodeDir, "/qr-with-defaults-java.png"));
     }
 
@@ -119,8 +122,8 @@ private static void decentRedColor(final URL resource, final QrCodeApi qrCodeApi
     private static void mineCraftCreeperColor(final URL resource, final QrCodeApi qrCodeApi, final String qrCodeDir) throws IOException {
         final BufferedImage logo = ImageIO.read(resource);
 
-        final var brighterGreen = Color.GREEN.brighter();
-        final var darkerGreen = Color.GREEN.darker()
+        final Color brighterGreen = Color.GREEN.brighter();
+        final Color darkerGreen = Color.GREEN.darker()
                                            .darker()
                                            .darker();
 
@@ -194,7 +197,7 @@ private static void drawQrCodeOnImage(final BufferedImage qrCode, final String q
         final URL url = Objects.requireNonNull(Main.class.getClassLoader()
                                                          .getResource("cup.jpg"));
         final BufferedImage mainImg = ImageIO.read(url);
-        final var graphics = mainImg.getGraphics();
+        final Graphics graphics = mainImg.getGraphics();
         graphics.drawImage(qrCode, 330, 600, null);
         graphics.dispose();
         ImageIO.write(mainImg, "png", new File(qrCodeDir, "/transparent-color-java.png"));
diff --git a/java-sample/src/main/java/io/github/simonscholz/QrCodeTypesMain.java b/java-sample/src/main/java/io/github/simonscholz/QrCodeTypesMain.java
index 9aa2237..83c1522 100644
--- a/java-sample/src/main/java/io/github/simonscholz/QrCodeTypesMain.java
+++ b/java-sample/src/main/java/io/github/simonscholz/QrCodeTypesMain.java
@@ -28,6 +28,10 @@ public static void main(final String[] args) throws IOException {
         Files.createDirectories(path);
         final var qrCodeDir = path.toAbsolutePath().toString();
 
+        generateSamples(qrCodeApi, qrCodeDir);
+    }
+
+    static void generateSamples(QrCodeApi qrCodeApi, String qrCodeDir) throws IOException {
         createWithUrl(qrCodeApi, qrCodeDir);
         createWithGeolocation(qrCodeApi, qrCodeDir);
         createWithEmail(qrCodeApi, qrCodeDir);
diff --git a/java-sample/src/test/java/io/github/simonscholz/QrCodeTest.java b/java-sample/src/test/java/io/github/simonscholz/QrCodeTest.java
new file mode 100644
index 0000000..45cae8a
--- /dev/null
+++ b/java-sample/src/test/java/io/github/simonscholz/QrCodeTest.java
@@ -0,0 +1,24 @@
+package io.github.simonscholz;
+
+import io.github.simonscholz.qrcode.QrCodeApi;
+import io.github.simonscholz.qrcode.QrCodeFactory;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.IOException;
+import java.nio.file.Path;
+
+public class QrCodeTest {
+
+    @Test
+    public void testMain(@TempDir Path tempDir) throws IOException {
+        QrCodeApi qrCodeApi = QrCodeFactory.createQrCodeApi();
+        Main.generateSamples(qrCodeApi, tempDir.toAbsolutePath().toString());
+    }
+
+    @Test
+    public void testQrCodeTypesMain(@TempDir Path tempDir) throws IOException {
+        QrCodeApi qrCodeApi = QrCodeFactory.createQrCodeApi();
+        QrCodeTypesMain.generateSamples(qrCodeApi, tempDir.toAbsolutePath().toString());
+    }
+}