diff --git a/src/main/java/org/springframework/samples/petclinic/vet/Vet.java b/src/main/java/org/springframework/samples/petclinic/vet/Vet.java
index 7a70155c3ea..d8a1fc84de7 100644
--- a/src/main/java/org/springframework/samples/petclinic/vet/Vet.java
+++ b/src/main/java/org/springframework/samples/petclinic/vet/Vet.java
@@ -57,10 +57,6 @@ protected Set<Specialty> getSpecialtiesInternal() {
 		return this.specialties;
 	}
 
-	protected void setSpecialtiesInternal(Set<Specialty> specialties) {
-		this.specialties = specialties;
-	}
-
 	@XmlElement
 	public List<Specialty> getSpecialties() {
 		List<Specialty> sortedSpecs = new ArrayList<>(getSpecialtiesInternal());
diff --git a/src/test/java/org/springframework/samples/petclinic/MySqlIntegrationTests.java b/src/test/java/org/springframework/samples/petclinic/MySqlIntegrationTests.java
index 300ac359ff9..31231d79e64 100644
--- a/src/test/java/org/springframework/samples/petclinic/MySqlIntegrationTests.java
+++ b/src/test/java/org/springframework/samples/petclinic/MySqlIntegrationTests.java
@@ -58,7 +58,7 @@ class MySqlIntegrationTests {
 	private RestTemplateBuilder builder;
 
 	@Test
-	void testFindAll() throws Exception {
+	void testFindAll() {
 		vets.findAll();
 		vets.findAll(); // served from cache
 	}
diff --git a/src/test/java/org/springframework/samples/petclinic/PetClinicIntegrationTests.java b/src/test/java/org/springframework/samples/petclinic/PetClinicIntegrationTests.java
index 6472a1212d4..6d982069686 100644
--- a/src/test/java/org/springframework/samples/petclinic/PetClinicIntegrationTests.java
+++ b/src/test/java/org/springframework/samples/petclinic/PetClinicIntegrationTests.java
@@ -44,7 +44,7 @@ public class PetClinicIntegrationTests {
 	private RestTemplateBuilder builder;
 
 	@Test
-	void testFindAll() throws Exception {
+	void testFindAll() {
 		vets.findAll();
 		vets.findAll(); // served from cache
 	}
diff --git a/src/test/java/org/springframework/samples/petclinic/PostgresIntegrationTests.java b/src/test/java/org/springframework/samples/petclinic/PostgresIntegrationTests.java
index 18945a57038..519081320fc 100644
--- a/src/test/java/org/springframework/samples/petclinic/PostgresIntegrationTests.java
+++ b/src/test/java/org/springframework/samples/petclinic/PostgresIntegrationTests.java
@@ -17,6 +17,7 @@
 package org.springframework.samples.petclinic;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assumptions.assumeTrue;
 
 import java.util.Arrays;
@@ -114,7 +115,16 @@ public void printProperties() {
 				Arrays.sort(names);
 				for (String name : names) {
 					String resolved = environment.getProperty(name);
-					String value = source.getProperty(name).toString();
+
+					assertNotNull(resolved, "resolved environment property: " + name + " is null.");
+
+					Object sourceProperty = source.getProperty(name);
+
+					assertNotNull(sourceProperty, "source property was expecting an object but is null.");
+
+					assertNotNull(sourceProperty.toString(), "source property toString() returned null.");
+
+					String value = sourceProperty.toString();
 					if (resolved.equals(value)) {
 						log.info(name + "=" + resolved);
 					}
diff --git a/src/test/java/org/springframework/samples/petclinic/owner/PetTypeFormatterTests.java b/src/test/java/org/springframework/samples/petclinic/owner/PetTypeFormatterTests.java
index dabade7b9e1..0295b47884d 100644
--- a/src/test/java/org/springframework/samples/petclinic/owner/PetTypeFormatterTests.java
+++ b/src/test/java/org/springframework/samples/petclinic/owner/PetTypeFormatterTests.java
@@ -68,7 +68,7 @@ void shouldParse() throws ParseException {
 	}
 
 	@Test
-	void shouldThrowParseException() throws ParseException {
+	void shouldThrowParseException() {
 		given(this.pets.findPetTypes()).willReturn(makePetTypes());
 		Assertions.assertThrows(ParseException.class, () -> {
 			petTypeFormatter.parse("Fish", Locale.ENGLISH);
diff --git a/src/test/java/org/springframework/samples/petclinic/service/ClinicServiceTests.java b/src/test/java/org/springframework/samples/petclinic/service/ClinicServiceTests.java
index 2cbf7af26b4..2f3d00ce6ea 100644
--- a/src/test/java/org/springframework/samples/petclinic/service/ClinicServiceTests.java
+++ b/src/test/java/org/springframework/samples/petclinic/service/ClinicServiceTests.java
@@ -205,8 +205,6 @@ void shouldAddNewVisitForPet() {
 		owner6.addVisit(pet7.getId(), visit);
 		this.owners.save(owner6);
 
-		owner6 = this.owners.findById(6);
-
 		assertThat(pet7.getVisits()) //
 			.hasSize(found + 1) //
 			.allMatch(value -> value.getId() != null);
diff --git a/src/test/java/org/springframework/samples/petclinic/system/CrashControllerTests.java b/src/test/java/org/springframework/samples/petclinic/system/CrashControllerTests.java
index 09773aec84c..cc2ad674620 100644
--- a/src/test/java/org/springframework/samples/petclinic/system/CrashControllerTests.java
+++ b/src/test/java/org/springframework/samples/petclinic/system/CrashControllerTests.java
@@ -30,7 +30,7 @@
 // luck ((plain(st) UNIT test)! :)
 class CrashControllerTests {
 
-	CrashController testee = new CrashController();
+	final CrashController testee = new CrashController();
 
 	@Test
 	void testTriggerException() {
diff --git a/src/test/java/org/springframework/samples/petclinic/vet/VetTests.java b/src/test/java/org/springframework/samples/petclinic/vet/VetTests.java
index b29c6d1009e..ec1aacf5c19 100644
--- a/src/test/java/org/springframework/samples/petclinic/vet/VetTests.java
+++ b/src/test/java/org/springframework/samples/petclinic/vet/VetTests.java
@@ -18,6 +18,7 @@
 import org.junit.jupiter.api.Test;
 import org.springframework.util.SerializationUtils;
 
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**