an obj ref = a remote control

each rcontrol is programmed to a target.
u can program your rcontrol to an Animal, or a Mammal, or a Dog, or erase all programming.

When your rcontrol is programmed for an Animal, bark() method is not available — the “bark” button is in a detachable extension and removed from the rcontrol. You need to cast.

Q: objects are passed by…?
A: well, u duplicate the rcontrol. A method receiving an arg need to duplicate the rcontrol and can’t reprogram the original rcontrol

Q: FINAL var (of a ref type) means?
A: non-reprogramable

interviewers’ favorite topics (2007

See also “halo”.
xp: These areas have received disproportional attention from interviewers. ranked.

* threading
* collections
Study iterator, comparator, hashCode()
Study load factor and capacity — asked by multiple financial giants

* outer join@@ not much depth
study join order, subquery

* interface, abstract@@ not much depth
* GC including finalize()
study generational GC, mem leak and jvm profilers

* deadlock
* servlet life cycle
* singleton, mvc, dao,
* vector ^ arraylist, or hashtable^hashmap
* list 1.5 features

roti [[oracle sql tun`]]

cost-based optimizer vs rule-based optimizer
optimizer modes — choose, rule, first_rows, all_rows
diminishing return, most significant queries to target
4 areas of ora tuning — instance, norm/denorm(with triggers), OS, SQL
self-join examples
oracle implementations of joining, in relation with subqueries
function-based index
what can disable an index
optimizer hints
sql cache
hash storage for often-joined tables
essential table-access methods
essential index-access methods
reading execution plans

java ServerSocket.accept()

I think this should be one of the first important yet tricky socket methods to study and /internalize/. Memorize it’s extended signature and you will understand how it relates to other things.

See P221 [[ java threads ]].

A real server jvm always creates and uses 2 *types* of sockets — a single well-known listening socket, which on demand creates a “private socket” (aka data socket) for each incoming client request.

The new socket manufactured by accept() has the remote address:port set to the client’s address:port and is already connected to it.

I think the new socket initiates the connection, therefore this socket is considered a “socket” and not a ServerSocket. Nothing found online to confirm this.

NY iview — meetup

q: with and without sub queries, write sql to show employees not assigned any project, given employee (id, name), employee_project (eid, pid)
%%A: outer join with count() = 0 ? Yes see post on payment history

http://sqlzoo.net/3.htm contains actors not casted

select count(name) from actor left outer join casting on actor.id=casting.actorid where casting.actorid is null

Based on IBM webpage: “The following query returns only rows in which customers have not made any calls

SELECT c.customer_num, c.lname, c.company, c.phone, u.call_dtime, u.call_descr
FROM customer c LEFT OUTER JOIN cust_calls u
ON c.customer_num = u.customer_num
WHERE u.customer_num IS NULL “

This is a case of a normal “unmatched prikey”. No referential integrity violation.

q: xp with mysql replication? (programmers need to know mysql replication.)

q: describe an xq java web project

q: difference btw spring mvc vs struts

q: java 5 features? generic, enum

q: describe a personal pet project (“side project”)

q: why do u say smarty is cleaner separation of presentation and logic than jsp or asp?

q: name a technology that excites u now and name one feature

q: php caching

q: php connection pool

q: unit testing?

q: ajax xp?

q: web services xp?

q: state sync between 2 instances of php?

%%q: important technical skills for this job
a: mysql cluster, fast sql queries, core java, junit,

hurix IV – web java + JMS

q: can an interface define member variables?
q: spring: how do u configure a spring mvc system?
q: struts: did u use validator, struts tags or tiles? How do u configure your struts app to use tiles?
q: if an abstract class defines a constructor, does the derived class constructor need to make an explicit call to it?
q: how does a web app in 1.war forward to a web app in 2.war? Is requestDispatcher used across web apps?
q: what’s the significance of hash value of an object
q: how do u implement a customized hash value based on the data encapsulated?
q: how do u make an arrayList of person objects sortable by birth date? How Can I sort this ArrayList?
q: what’s the traditional solution to the problem enum is designed to solve?
q: from the definition of home and remote interface, can u tell the difference between a slsb and a sfsb?
q: for a mdb, which method must u write? which interface/base-class is it part of?
q: if a jms requester sends requests about person 1, 2 and 3 to a queue, and need the server to reply on the same person 1, 2 and 3, how does JMS support it? (I think the reply must specify “this is for Person X”)