Migrating Mule 3.6 to Mule 3.7 NullPointerException calling method with null payload

问题

I'm migrating my mule project from version 3.6 to 3.7. In version 3.6 I was able to use invoker calling a method passing payload as an argument.

Now in version 3.7 if I do that I get NullPointerException, when payload is null, in class InvokerMessageProcessor, line 272, when the following test is executed:

if (!(type.isAssignableFrom(arg.getClass()))) 

Because when payload is null arg is null.

Is this a bug?

回答1:

In fact, there was a change in the way Mule treats emptiness and null values from Mule 3.6+ to 3.7+, This is the way the validations used to be in Mule 3.6.x for different kind of processors and components:

• MEL (Mule Expression Language): Payload == null: false
• MEL: Payload is NullPayload: true
• MEL: Payload is org.mule.transport.NullPayload: true
• Groovy: Payload instanceof org.mule.transport.NullPayload: true

• Groovy: Payload == null: false

  Now, in Mule 3.7.x:

• MEL: Payload == null: true

• MEL: Payload is NullPayload: false
• MEL: Payload is org.mule.transport.NullPayload: false
• Groovy: Payload instanceof org.mule.transport.NullPayload: true
• Groovy: Payload == null: false

来源：https://stackoverflow.com/questions/35850469/migrating-mule-3-6-to-mule-3-7-nullpointerexception-calling-method-with-null-pay