The creditCard property is a to-one relationship that Direct to Java Client expands to the identify property keys (cardNumber and authorizationNum) of the relationship's destination entity (a CreditCard). By removing creditCard from the property keys, you remove the cardNumber and authorizationNum fields from the query interface.
Two other Customer properties, memberSince and phone, seem like reasonable attributes to query on, so add them.
The results table is far too crowded with properties to be useful, so pare down the set of list property keys. Remove state, streetAddress, zip, and creditCard from the list property keys. Order the remaining keys as follows: firstName, lastName, city, phone, memberSince.