fix: replace placeholder message with a helpful error message

src/main/java/org/eclipse/yasson/internal/properties/MessageKeys.java

diff --git a/src/main/java/org/eclipse/yasson/internal/properties/MessageKeys.java b/src/main/java/org/eclipse/yasson/internal/properties/MessageKeys.java
index fde557a..2171f8b 100644
--- a/src/main/java/org/eclipse/yasson/internal/properties/MessageKeys.java
+++ b/src/main/java/org/eclipse/yasson/internal/properties/MessageKeys.java
@@ -285,6 +285,10 @@
      */
     PROPERTY_NAME_CLASH("propertyNameClash"),
     /**
+     * A {@code @JsonbTypeInfo} discriminator key collides with a property name on the implementing class.
+     */
+    TYPE_INFO_KEY_CLASH("typeInfoKeyClash"),
+    /**
      * {@link Date} is not supported I-Json is enabled.
      */
     SQL_DATE_IJSON_ERROR("sqlDateIJsonError"),

src/main/java/org/eclipse/yasson/internal/serializer/SerializationModelCreator.java

diff --git a/src/main/java/org/eclipse/yasson/internal/serializer/SerializationModelCreator.java b/src/main/java/org/eclipse/yasson/internal/serializer/SerializationModelCreator.java
index 9aa29a7..c7870b7 100644
--- a/src/main/java/org/eclipse/yasson/internal/serializer/SerializationModelCreator.java
+++ b/src/main/java/org/eclipse/yasson/internal/serializer/SerializationModelCreator.java
@@ -237,7 +237,10 @@
         }
         for (PropertyModel propertyModel : classModel.getSortedProperties()) {
             if (propertySerializers.containsKey(propertyModel.getWriteName())) {
-                throw new JsonbException("CHANGE naming conflict!");
+                throw new JsonbException(Messages.getMessage(MessageKeys.TYPE_INFO_KEY_CLASH,
+                        typeInheritanceConfiguration.getFieldName(),
+                        propertyModel.getWriteName(),
+                        classModel.getType().getName()));
             }
         }
     }

src/main/resources/yasson-messages.properties

diff --git a/src/main/resources/yasson-messages.properties b/src/main/resources/yasson-messages.properties
index 244df20..59b7d23 100644
--- a/src/main/resources/yasson-messages.properties
+++ b/src/main/resources/yasson-messages.properties
@@ -81,6 +81,7 @@
 jsonbTransientWithOtherAnnotations=JsonbTransient annotation cannot be used with other jsonb annotations on the same property.
 nonParametrizedType=Type: {0} is not a parametrized type.
 propertyNameClash=Property {0} clashes with property {1} by read or write name in class {2}.
+typeInfoKeyClash=@JsonbTypeInfo discriminator key ''{0}'' conflicts with property ''{1}'' in class {2}. Rename the property or change the @JsonbTypeInfo key.
 sqlDateIJsonError=java.sql.Date is not supported in STRICT_IJSON mode.
 recursiveReference=Recursive reference has been found in {0}.
 datatypeFactoryCreationFailed=An error occurred while DatatypeFactory creation.