fix: self review

diff --git a/src/test/java/org/eclipse/yasson/customization/transients/JsonbTransientTest.java b/src/test/java/org/eclipse/yasson/customization/transients/JsonbTransientTest.java
index 6fdd085..5d2f053 100644
--- a/src/test/java/org/eclipse/yasson/customization/transients/JsonbTransientTest.java
+++ b/src/test/java/org/eclipse/yasson/customization/transients/JsonbTransientTest.java

@@ -189,21 +189,20 @@
     @Test
     public void testJsonbTransientInheritedFromAbstractMethodInInterfaceAndClass() {
         final String EXPECTED = "{\"field2\":\"bbb\"}";
-        Jsonb jsonb = JsonbBuilder.create(new JsonbConfig());
-        assertEquals(EXPECTED, jsonb.toJson(new TransientAbstractInterface() {
+        assertEquals(EXPECTED, defaultJsonb.toJson(new TransientAbstractInterface() {
             @Override
             public String getField1() { return "aaa"; }
             @Override
             public String getField2() { return "bbb"; }
         }));
-        assertEquals(EXPECTED, jsonb.toJson(new TransientAbstractClass() {
+        assertEquals(EXPECTED, defaultJsonb.toJson(new TransientAbstractClass() {
             @Override
             public String getField1() { return "aaa"; }
             @Override
             public String getField2() { return "bbb"; }
         }));
-        assertEquals(EXPECTED, jsonb.toJson(new TransientAbstractClassImpl()));
-        assertEquals(EXPECTED, jsonb.toJson(new TransientAbstractClassImpl() {}));
+        assertEquals(EXPECTED, defaultJsonb.toJson(new TransientAbstractClassImpl()));
+        assertEquals(EXPECTED, defaultJsonb.toJson(new TransientAbstractClassImpl() {}));
     }
 
     /** Interface whose {@code getField1} getter is annotated {@link JsonbTransient}. */

diff --git a/src/test/java/org/eclipse/yasson/defaultmapping/specific/SerializationExceptionTest.java b/src/test/java/org/eclipse/yasson/defaultmapping/specific/SerializationExceptionTest.java
index 6dca56d..80f652f 100644
--- a/src/test/java/org/eclipse/yasson/defaultmapping/specific/SerializationExceptionTest.java
+++ b/src/test/java/org/eclipse/yasson/defaultmapping/specific/SerializationExceptionTest.java

@@ -13,6 +13,7 @@
 
 package org.eclipse.yasson.defaultmapping.specific;
 
+import static org.eclipse.yasson.Jsonbs.defaultJsonb;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
@@ -40,7 +41,7 @@
      */
     @Test
     public void getterExceptionPropagatesAsJsonbException() {
-        assertThrows(JsonbException.class, () -> JsonbBuilder.create().toJson(new BrokenGetterPojo()));
+        assertThrows(JsonbException.class, () -> defaultJsonb.toJson(new BrokenGetterPojo()));
     }
 
     /**
@@ -58,7 +59,7 @@
 
         @Override
         public String toString() {
-            return JsonbBuilder.create().toJson(this);
+            return defaultJsonb.toJson(this);
         }
     }
 }