[Java client] Improve error reporting for invalid addresses

In the following example, the second address should throw an exception notifying that the request type is different from the already present object

1. java -cp ${CLASSPATH} org.apache.qpid.example.Spout "ex;{create:sender, node: {type:topic,x-declare:

{type:topic}

}}"
2. java -cp ${CLASSPATH} org.apache.qpid.example.Spout "ex;{create:sender, node: {type:topic,x-declare:

{type:fanout}

}}"

Also we need to provide a clear messages when an assertion is false.
Ex.
1. java -cp ${CLASSPATH} org.apache.qpid.example.Spout "ex;{create:sender, node: {type:topic,x-declare:

{type:topic}

}}"
2. java -cp ${CLASSPATH} org.apache.qpid.example.Spout "ex;{assert:sender, node: {type:topic,x-declare:

{type:fanout}

}}"

All though we currently throw an exception, the message is not very useful.