diff --git a/core/pom.xml b/core/pom.xml
index e484f03..956667e 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -31,6 +31,13 @@
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-surefire-plugin</artifactId>
 				<version>3.0.0-M5</version>
+				<configuration>
+					<argLine>
+						${argLine}
+						--add-opens dev.kske.eventbus.core/dev.kske.eventbus.core=ALL-UNNAMED
+						--add-opens dev.kske.eventbus.core/dev.kske.eventbus.core.handler=ALL-UNNAMED
+					</argLine>
+				</configuration>
 			</plugin>
 
 			<!-- Generate coverage report -->
diff --git a/core/src/test/java/dev/kske/eventbus/core/CancelTest.java b/core/src/test/java/dev/kske/eventbus/core/CancelTest.java
index 581f300..5f715c7 100644
--- a/core/src/test/java/dev/kske/eventbus/core/CancelTest.java
+++ b/core/src/test/java/dev/kske/eventbus/core/CancelTest.java
@@ -11,7 +11,7 @@ import org.junit.jupiter.api.*;
  * @author Leon Hofmeister
  * @since 0.1.0
  */
-public class CancelTest {
+class CancelTest {
 
 	EventBus	bus;
 	int			hits;
@@ -22,7 +22,7 @@ public class CancelTest {
 	 * @since 0.1.0
 	 */
 	@BeforeEach
-	public void registerListener() {
+	void registerListener() {
 		bus = new EventBus();
 		bus.registerListener(this);
 	}
@@ -34,7 +34,7 @@ public class CancelTest {
 	 * @since 0.1.0
 	 */
 	@Test
-	public void testCancellation() {
+	void testCancellation() {
 		bus.dispatch(new SimpleEvent());
 		assertEquals(1, hits);
 	}
diff --git a/core/src/test/java/dev/kske/eventbus/core/DeadTest.java b/core/src/test/java/dev/kske/eventbus/core/DeadTest.java
index ac4d862..ccef35c 100644
--- a/core/src/test/java/dev/kske/eventbus/core/DeadTest.java
+++ b/core/src/test/java/dev/kske/eventbus/core/DeadTest.java
@@ -10,7 +10,7 @@ import org.junit.jupiter.api.Test;
  * @author Kai S. K. Engelbart
  * @since 1.1.0
  */
-public class DeadTest {
+class DeadTest {
 
 	EventBus	bus		= new EventBus();
 	String		event	= "This event has no handler";
@@ -22,7 +22,7 @@ public class DeadTest {
 	 * @since 1.1.0
 	 */
 	@Test
-	public void testDeadEvent() {
+	void testDeadEvent() {
 		bus.registerListener(this);
 		bus.dispatch(event);
 		assertTrue(deadEventHandled);
@@ -36,7 +36,7 @@ public class DeadTest {
 	 * @since 1.1.0
 	 */
 	@Test
-	public void testUnhandledDeadEvent() {
+	void testUnhandledDeadEvent() {
 		bus.dispatch(event);
 	}
 
diff --git a/core/src/test/java/dev/kske/eventbus/core/DispatchTest.java b/core/src/test/java/dev/kske/eventbus/core/DispatchTest.java
index 7e8e412..cfd4de1 100644
--- a/core/src/test/java/dev/kske/eventbus/core/DispatchTest.java
+++ b/core/src/test/java/dev/kske/eventbus/core/DispatchTest.java
@@ -12,7 +12,7 @@ import org.junit.jupiter.api.*;
  */
 @Polymorphic
 @Priority(150)
-public class DispatchTest {
+class DispatchTest {
 
 	EventBus	bus;
 	static int	hits;
@@ -23,7 +23,7 @@ public class DispatchTest {
 	 * @since 0.0.1
 	 */
 	@BeforeEach
-	public void registerListener() {
+	void registerListener() {
 		bus = new EventBus();
 		bus.registerListener(this);
 		bus.registerListener(SimpleEvent.class, e -> {
@@ -39,7 +39,7 @@ public class DispatchTest {
 	 * @since 0.0.1
 	 */
 	@Test
-	public void testDispatch() {
+	void testDispatch() {
 		bus.dispatch(new SimpleEventSub());
 		bus.dispatch(new SimpleEvent());
 	}
@@ -50,7 +50,7 @@ public class DispatchTest {
 	 * @since 1.2.0
 	 */
 	@Test
-	public void testDebugExecutionOrder() {
+	void testDebugExecutionOrder() {
 		String executionOrder = bus.debugExecutionOrder(SimpleEvent.class);
 		System.out.println(executionOrder);
 		assertEquals(
diff --git a/core/src/test/java/dev/kske/eventbus/core/ExceptionTest.java b/core/src/test/java/dev/kske/eventbus/core/ExceptionTest.java
index fcc4b61..8bef526 100644
--- a/core/src/test/java/dev/kske/eventbus/core/ExceptionTest.java
+++ b/core/src/test/java/dev/kske/eventbus/core/ExceptionTest.java
@@ -10,7 +10,7 @@ import org.junit.jupiter.api.Test;
  * @author Kai S. K. Engelbart
  * @since 1.1.0
  */
-public class ExceptionTest {
+class ExceptionTest {
 
 	EventBus			bus			= new EventBus();
 	String				event		= "This event will cause an exception";
@@ -23,7 +23,7 @@ public class ExceptionTest {
 	 * @since 1.1.0
 	 */
 	@Test
-	public void testExceptionEvent() {
+	void testExceptionEvent() {
 		bus.registerListener(this);
 		bus.registerListener(new ExceptionListener());
 		bus.dispatch(event);
@@ -38,7 +38,7 @@ public class ExceptionTest {
 	 * @since 1.1.0
 	 */
 	@Test
-	public void testUnhandledExceptionEvent() {
+	void testUnhandledExceptionEvent() {
 		bus.registerListener(this);
 		bus.dispatch(event);
 		bus.removeListener(this);
diff --git a/core/src/test/java/dev/kske/eventbus/core/ExceptionWrapperTest.java b/core/src/test/java/dev/kske/eventbus/core/ExceptionWrapperTest.java
index 56f2bd9..04b4a69 100644
--- a/core/src/test/java/dev/kske/eventbus/core/ExceptionWrapperTest.java
+++ b/core/src/test/java/dev/kske/eventbus/core/ExceptionWrapperTest.java
@@ -10,7 +10,7 @@ import org.junit.jupiter.api.Test;
  * @author Kai S. K. Engelbart
  * @since 1.2.1
  */
-public class ExceptionWrapperTest {
+class ExceptionWrapperTest {
 
 	EventBus	bus		= new EventBus();
 	String		event	= "This event will cause an exception";
@@ -21,7 +21,7 @@ public class ExceptionWrapperTest {
 	 * @since 1.2.1
 	 */
 	@Test
-	public void testExceptionWrapper() {
+	void testExceptionWrapper() {
 		bus.registerListener(this);
 		assertThrows(ExceptionWrapper.class, () -> bus.dispatch(event));
 	}
diff --git a/core/src/test/java/dev/kske/eventbus/core/NestedTest.java b/core/src/test/java/dev/kske/eventbus/core/NestedTest.java
index c8d3862..bb0670e 100644
--- a/core/src/test/java/dev/kske/eventbus/core/NestedTest.java
+++ b/core/src/test/java/dev/kske/eventbus/core/NestedTest.java
@@ -10,7 +10,7 @@ import org.junit.jupiter.api.*;
  * @author Kai S. K. Engelbart
  * @since 1.2.0
  */
-public class NestedTest {
+class NestedTest {
 
 	EventBus	bus;
 	boolean		nestedHit;
@@ -21,7 +21,7 @@ public class NestedTest {
 	 * @since 1.2.0
 	 */
 	@BeforeEach
-	public void registerListener() {
+	void registerListener() {
 		bus = new EventBus();
 		bus.registerListener(this);
 	}
@@ -34,7 +34,7 @@ public class NestedTest {
 	 * @since 1.2.0
 	 */
 	@Test
-	public void testNestedDispatch() {
+	void testNestedDispatch() {
 		bus.dispatch(new SimpleEvent());
 		assertTrue(nestedHit);
 	}
diff --git a/core/src/test/java/dev/kske/eventbus/core/SimpleEvent.java b/core/src/test/java/dev/kske/eventbus/core/SimpleEvent.java
index bed60bc..2baf080 100644
--- a/core/src/test/java/dev/kske/eventbus/core/SimpleEvent.java
+++ b/core/src/test/java/dev/kske/eventbus/core/SimpleEvent.java
@@ -6,4 +6,4 @@ package dev.kske.eventbus.core;
  * @author Kai S. K. Engelbart
  * @since 0.0.1
  */
-public class SimpleEvent {}
+class SimpleEvent {}
diff --git a/core/src/test/java/dev/kske/eventbus/core/SimpleEventSub.java b/core/src/test/java/dev/kske/eventbus/core/SimpleEventSub.java
index c519fc8..909836e 100644
--- a/core/src/test/java/dev/kske/eventbus/core/SimpleEventSub.java
+++ b/core/src/test/java/dev/kske/eventbus/core/SimpleEventSub.java
@@ -6,4 +6,4 @@ package dev.kske.eventbus.core;
  * @author Kai S. K. Engelbart
  * @since 0.0.4
  */
-public class SimpleEventSub extends SimpleEvent {}
+class SimpleEventSub extends SimpleEvent {}