diff --git a/src/main/java/org/junitpioneer/internal/PioneerAnnotationUtils.java b/src/main/java/org/junitpioneer/internal/PioneerAnnotationUtils.java
index 4414d5953..171f29369 100644
--- a/src/main/java/org/junitpioneer/internal/PioneerAnnotationUtils.java
+++ b/src/main/java/org/junitpioneer/internal/PioneerAnnotationUtils.java
@@ -250,7 +250,7 @@ private static <A extends Annotation> List<A> findOnType(Class<?> element, Class
 				.collect(Collectors.toList());
 	}
 
-	public static List<? extends Annotation> findParameterArgumentsSources(Method testMethod) {
+	public static List<Annotation> findParameterArgumentsSources(Method testMethod) {
 		return Arrays
 				.stream(testMethod.getParameters())
 				.map(PioneerAnnotationUtils::collectArgumentSources)
diff --git a/src/main/java/org/junitpioneer/jupiter/RetryingTestExtension.java b/src/main/java/org/junitpioneer/jupiter/RetryingTestExtension.java
index 83d53b1a2..553bb384a 100644
--- a/src/main/java/org/junitpioneer/jupiter/RetryingTestExtension.java
+++ b/src/main/java/org/junitpioneer/jupiter/RetryingTestExtension.java
@@ -125,7 +125,7 @@ else if (maxAttempts <= minSuccess) {
 			return new FailedTestRetrier(maxAttempts, minSuccess, retryingTest.onExceptions(), formatter);
 		}
 
-		void failed(Throwable exception) throws Throwable {
+		<E extends Throwable> void failed(E exception) throws E {
 			exceptionsSoFar++;
 
 			if (exception instanceof TestAbortedException) {
diff --git a/src/main/java/org/junitpioneer/jupiter/StdOut.java b/src/main/java/org/junitpioneer/jupiter/StdOut.java
index 3219b179e..a035eb99f 100644
--- a/src/main/java/org/junitpioneer/jupiter/StdOut.java
+++ b/src/main/java/org/junitpioneer/jupiter/StdOut.java
@@ -25,8 +25,8 @@ public class StdOut extends OutputStream {
 
 	private final StringWriter writer = new StringWriter();
 
-	// recreate default constructor to prevent compiler warning
 	public StdOut() {
+		// recreate default constructor to prevent compiler warning
 	}
 
 	@Override
diff --git a/src/main/java/org/junitpioneer/jupiter/cartesian/ArgumentSets.java b/src/main/java/org/junitpioneer/jupiter/cartesian/ArgumentSets.java
index 597c9c43a..7f21c05b9 100644
--- a/src/main/java/org/junitpioneer/jupiter/cartesian/ArgumentSets.java
+++ b/src/main/java/org/junitpioneer/jupiter/cartesian/ArgumentSets.java
@@ -35,10 +35,10 @@
  */
 public class ArgumentSets {
 
-	private final List<List<?>> argumentSets;
+	private final List<List<?>> arguments;
 
 	private ArgumentSets() {
-		this.argumentSets = new ArrayList<>();
+		this.arguments = new ArrayList<>();
 	}
 
 	private ArgumentSets(Collection<?> arguments) {
@@ -47,7 +47,7 @@ private ArgumentSets(Collection<?> arguments) {
 	}
 
 	private ArgumentSets add(Collection<?> arguments) {
-		argumentSets.add(new ArrayList<>(arguments));
+		this.arguments.add(new ArrayList<>(arguments));
 		return this;
 	}
 
@@ -149,7 +149,7 @@ public final <T> ArgumentSets argumentsForNextParameter(Stream<T> arguments) {
 	}
 
 	List<List<?>> getArguments() {
-		return argumentSets;
+		return arguments;
 	}
 
 }
diff --git a/src/main/java/org/junitpioneer/jupiter/json/AbstractJsonArgumentsProvider.java b/src/main/java/org/junitpioneer/jupiter/json/AbstractJsonArgumentsProvider.java
index c25cc8767..487668132 100644
--- a/src/main/java/org/junitpioneer/jupiter/json/AbstractJsonArgumentsProvider.java
+++ b/src/main/java/org/junitpioneer/jupiter/json/AbstractJsonArgumentsProvider.java
@@ -40,7 +40,7 @@ public Stream<Object> provideArguments(ExtensionContext context, Parameter param
 	}
 
 	private Stream<Node> provideNodes(ExtensionContext context) {
-		return provideNodes(context, JsonConverterProvider.getJsonConverter(context));
+		return provideNodes(context, JsonConverterProvider.getJsonConverter());
 	}
 
 	protected abstract Stream<Node> provideNodes(ExtensionContext context, JsonConverter jsonConverter);
diff --git a/src/main/java/org/junitpioneer/jupiter/json/JacksonJsonConverter.java b/src/main/java/org/junitpioneer/jupiter/json/JacksonJsonConverter.java
index 8948982bc..65b87ec02 100644
--- a/src/main/java/org/junitpioneer/jupiter/json/JacksonJsonConverter.java
+++ b/src/main/java/org/junitpioneer/jupiter/json/JacksonJsonConverter.java
@@ -39,7 +39,6 @@ class JacksonJsonConverter implements JsonConverter {
 	@Override
 	public Node toNode(InputStream stream) {
 		try {
-			ObjectMapper objectMapper = getObjectMapper(false);
 			JsonNode jsonNode = objectMapper.readTree(stream);
 			return new JacksonNode(objectMapper, jsonNode);
 		}
diff --git a/src/main/java/org/junitpioneer/jupiter/json/JacksonNode.java b/src/main/java/org/junitpioneer/jupiter/json/JacksonNode.java
index 7ff9cf29d..fe13a1c86 100644
--- a/src/main/java/org/junitpioneer/jupiter/json/JacksonNode.java
+++ b/src/main/java/org/junitpioneer/jupiter/json/JacksonNode.java
@@ -39,7 +39,7 @@ public boolean isArray() {
 
 	@Override
 	public Stream<Node> elements() {
-		return StreamSupport.stream(node.spliterator(), false).map(node -> new JacksonNode(objectMapper, node));
+		return StreamSupport.stream(node.spliterator(), false).map(element -> new JacksonNode(objectMapper, element));
 	}
 
 	@Override
diff --git a/src/main/java/org/junitpioneer/jupiter/json/JsonConverterProvider.java b/src/main/java/org/junitpioneer/jupiter/json/JsonConverterProvider.java
index 8f308269f..a5de0a74b 100644
--- a/src/main/java/org/junitpioneer/jupiter/json/JsonConverterProvider.java
+++ b/src/main/java/org/junitpioneer/jupiter/json/JsonConverterProvider.java
@@ -10,24 +10,22 @@
 
 package org.junitpioneer.jupiter.json;
 
-import org.junit.jupiter.api.extension.ExtensionContext;
-
 class JsonConverterProvider {
 
-	private static final boolean jacksonPresent = isClassPresent("com.fasterxml.jackson.databind.ObjectMapper");
+	private static final boolean JACKSON_PRESENT = isJacksonObjectMapperClassPresent();
 
-	static boolean isClassPresent(String className) {
+	static boolean isJacksonObjectMapperClassPresent() {
 		try {
-			JsonConverterProvider.class.getClassLoader().loadClass(className);
+			JsonConverterProvider.class.getClassLoader().loadClass("com.fasterxml.jackson.databind.ObjectMapper");
 			return true;
 		}
-		catch (Throwable e) {
+		catch (Exception e) {
 			return false;
 		}
 	}
 
-	static JsonConverter getJsonConverter(ExtensionContext context) {
-		if (jacksonPresent) {
+	static JsonConverter getJsonConverter() {
+		if (JACKSON_PRESENT) {
 			return JacksonJsonConverter.getConverter();
 		}
 
diff --git a/src/test/java/org/junitpioneer/jupiter/json/NoJsonParserConfiguredExceptionTest.java b/src/test/java/org/junitpioneer/jupiter/json/NoJsonParserConfiguredExceptionTest.java
new file mode 100644
index 000000000..031deddb9
--- /dev/null
+++ b/src/test/java/org/junitpioneer/jupiter/json/NoJsonParserConfiguredExceptionTest.java
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2016-2022 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v2.0 which
+ * accompanies this distribution and is available at
+ *
+ * http://www.eclipse.org/legal/epl-v20.html
+ */
+
+package org.junitpioneer.jupiter.json;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+class NoJsonParserConfiguredExceptionTest {
+
+	@Test
+	void shouldBeUnchecked() {
+		assertThat(new NoJsonParserConfiguredException()).isInstanceOf(RuntimeException.class);
+	}
+
+}