Javadoc in JPA 2.1 section 3.1.1 mentions that a IAE will be thrown. Also see additional quote below from text following javadoc that explains what happens when runtime exceptions are thrown (other than LockTimeoutException):

/**
* Create an instance of Query for executing a named query
* (in the Java Persistence query language or in native SQL).
* @param name the name of a query defined in metadata
* @return the new query instance
* @throws IllegalArgumentException if a query has not been
*
 defined with the given name or if the query string is
*
 found to be invalid
*/
public Query createNamedQuery(String name);

Runtime exceptions thrown by the methods of the EntityManager interface other than the Lock-
TimeoutException will cause the current transaction to be marked for rollback if the persistence
context is joined to that transaction.

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