diff --git a/src/test/java/org/eclipse/yasson/adapters/AdaptersTest.java b/src/test/java/org/eclipse/yasson/adapters/AdaptersTest.java
index ec929c71..54260a8d 100644
--- a/src/test/java/org/eclipse/yasson/adapters/AdaptersTest.java
+++ b/src/test/java/org/eclipse/yasson/adapters/AdaptersTest.java
@@ -632,14 +632,11 @@ public void testAdaptedRootType() throws Exception {
     }
 
     @Test
-    public void testCustomAdapterInEnum() throws Exception {
-        try (Jsonb jsonb = JsonbBuilder.create()) {
+    public void testCustomAdapterInEnum() {
+        Vegetables expected = Vegetables.TOMATO;
 
-            Vegetables expected = Vegetables.TOMATO;
+        String expectedJson = defaultJsonb.toJson(expected);
 
-            String expectedJson = jsonb.toJson(expected);
-
-            assertEquals(expected, jsonb.fromJson(expectedJson, Vegetables.class));
-        }
+        assertEquals(expected, defaultJsonb.fromJson(expectedJson, Vegetables.class));
     }
 }
diff --git a/src/test/java/org/eclipse/yasson/defaultmapping/generics/GenericsTest.java b/src/test/java/org/eclipse/yasson/defaultmapping/generics/GenericsTest.java
index 3261c0c8..90c1f718 100644
--- a/src/test/java/org/eclipse/yasson/defaultmapping/generics/GenericsTest.java
+++ b/src/test/java/org/eclipse/yasson/defaultmapping/generics/GenericsTest.java
@@ -425,18 +425,16 @@ public void collectionWrapperTest() {
     }
 
     @Test
-    public void multipleGenericLevels() throws Exception {
+    public void multipleGenericLevels() {
         FinalMember member = new FinalMember();
         member.setName("Jason");
         FinalGenericWrapper concreteContainer = new FinalGenericWrapper();
         concreteContainer.setMember(member);
 
         String expected = "{\"member\":{\"name\":\"Jason\"}}";
-        try (Jsonb jsonb = JsonbBuilder.create()) {
-            assertEquals(expected, jsonb.toJson(concreteContainer));
-            FinalGenericWrapper finalGenericWrapper = jsonb.fromJson(expected, FinalGenericWrapper.class);
-            assertEquals(concreteContainer, finalGenericWrapper);
-        }
+        assertEquals(expected, defaultJsonb.toJson(concreteContainer));
+        FinalGenericWrapper finalGenericWrapper = defaultJsonb.fromJson(expected, FinalGenericWrapper.class);
+        assertEquals(concreteContainer, finalGenericWrapper);
     }
 
     @Test
@@ -451,18 +449,16 @@ public void lowerBoundTypeVariableInCollectionAttribute() throws Exception {
         
         List<AnotherGenericTestClass<Integer, Shape>> asList = List.of(anotherGenericTestClass);
         
-        try (Jsonb jsonb = JsonbBuilder.create()) {
-            String toJson = jsonb.toJson(asList);
+        String toJson = defaultJsonb.toJson(asList);
 
-            Field field = LowerBoundTypeVariableWithCollectionAttributeClass.class.getDeclaredField("value");
+        Field field = LowerBoundTypeVariableWithCollectionAttributeClass.class.getDeclaredField("value");
 
-            Type genericType = field.getGenericType();
+        Type genericType = field.getGenericType();
 
-            List<AnotherGenericTestClass<Integer, Shape>> fromJson = jsonb.fromJson(toJson, genericType);
+        List<AnotherGenericTestClass<Integer, Shape>> fromJson = defaultJsonb.fromJson(toJson, genericType);
 
-            assertEquals(5, fromJson.get(0).field2.getArea());
-            assertEquals(6, fromJson.get(0).field1);
-        }
+        assertEquals(5, fromJson.get(0).field2.getArea());
+        assertEquals(6, fromJson.get(0).field1);
     }
     
     public interface FunctionalInterface<T> {
diff --git a/src/test/java/org/eclipse/yasson/serializers/SerializersTest.java b/src/test/java/org/eclipse/yasson/serializers/SerializersTest.java
index 18c2e057..5d63c138 100644
--- a/src/test/java/org/eclipse/yasson/serializers/SerializersTest.java
+++ b/src/test/java/org/eclipse/yasson/serializers/SerializersTest.java
@@ -541,18 +541,16 @@ public void testSerializeMapWithNullsForceArraySerializer() throws Exception {
      * Map shall be stored as a single JsonObject with keys as object properties names.
      */
     @Test
-    public void testSerializeMapToJsonObject() throws Exception {
+    public void testSerializeMapToJsonObject() {
         Map<String, Object> map = new HashMap<>();
-        try (Jsonb jsonb = JsonbBuilder.create(new JsonbConfig())) {
-            map.put("name", "John SMith");
-            map.put("age", 35);
-            map.put("married", true);
-            String json = jsonb.toJson(map);
-            JsonObject jobj = Json.createReader(new StringReader(json)).read().asJsonObject();
-            assertEquals("John SMith", jobj.getString("name"));
-            assertEquals(35, jobj.getInt("age"));
-			assertTrue(jobj.getBoolean("married"));
-        }
+        map.put("name", "John SMith");
+        map.put("age", 35);
+        map.put("married", true);
+        String json = defaultJsonb.toJson(map);
+        JsonObject jobj = Json.createReader(new StringReader(json)).read().asJsonObject();
+        assertEquals("John SMith", jobj.getString("name"));
+        assertEquals(35, jobj.getInt("age"));
+        assertTrue(jobj.getBoolean("married"));
     }
 
     @Test
@@ -876,52 +874,40 @@ public void testBoxToArrayWithLambda() {
     }
 
     @Test
-    public void testCustomSerializersInContainer() throws Exception {
-        try (Jsonb jsonb = JsonbBuilder.create()) {
-
-            Container expected = new Container(List.of(new Containee("k", "v")));
+    public void testCustomSerializersInContainer() {
+        Container expected = new Container(List.of(new Containee("k", "v")));
 
-            String expectedJson = jsonb.toJson(expected);
-            System.out.println(expectedJson);
+        String expectedJson = defaultJsonb.toJson(expected);
+        System.out.println(expectedJson);
 
-            assertEquals(expected, jsonb.fromJson(expectedJson, Container.class));
-        }
+        assertEquals(expected, defaultJsonb.fromJson(expectedJson, Container.class));
     }
 
     @Test
-    public void testCustomSerializersAndDeserializersInEnum() throws Exception {
-        try (Jsonb jsonb = JsonbBuilder.create()) {
+    public void testCustomSerializersAndDeserializersInEnum() {
+        Colors expected = Colors.GREEN;
 
-            Colors expected = Colors.GREEN;
+        String expectedJson = defaultJsonb.toJson(expected);
 
-            String expectedJson = jsonb.toJson(expected);
-
-            assertEquals(expected, jsonb.fromJson(expectedJson, Colors.class));
-        }
+        assertEquals(expected, defaultJsonb.fromJson(expectedJson, Colors.class));
     }
 
     @Test
-    public void testJsonbPropertyInEnum() throws Exception {
-        try (Jsonb jsonb = JsonbBuilder.create()) {
+    public void testJsonbPropertyInEnum() {
+        Cars expected = Cars.FORD;
 
-            Cars expected = Cars.FORD;
+        String expectedJson = defaultJsonb.toJson(expected);
 
-            String expectedJson = jsonb.toJson(expected);
-
-            assertEquals(expected, jsonb.fromJson(expectedJson, Cars.class));
-        }
+        assertEquals(expected, defaultJsonb.fromJson(expectedJson, Cars.class));
     }
 
     @Test
-    public void testNoJsonbPropertyInEnum() throws Exception {
-        try (Jsonb jsonb = JsonbBuilder.create()) {
+    public void testNoJsonbPropertyInEnum() {
+        Cars expected = Cars.FIAT;
 
-            Cars expected = Cars.FIAT;
+        String expectedJson = defaultJsonb.toJson(expected);
 
-            String expectedJson = jsonb.toJson(expected);
-
-            assertEquals(expected, jsonb.fromJson(expectedJson, Cars.class));
-        }
+        assertEquals(expected, defaultJsonb.fromJson(expectedJson, Cars.class));
     }
 
 }