Java Message Service, 2nd Edition

Nonexistent Properties

If a JMS client attempts to access a nonexistent property using getObjectProperty(), null is returned. The rest of the property methods attempt to convert the null value to the requested type using the valueOf() operations. This results in some interesting behavior. The getStringProperty() returns a null or possibly an empty String ("") depending on the implementation. The getBooleanProperty() method returns false for null values, while the other primitive property methods throw the java.lang.NumberFormatException.

The propertyExists() method can be used to avoid erroneous values or exceptions for properties that have not been set on the message. Here is an example of how it’s used:

if (message.propertyExists("Age"))
   age = message.getIntProperty("Age");
}