Oracle Applications Software Developer I interview questions

Write a object onto file using serailization, Had to write the code.

architecture of my application. 6) lazy loading. 7) which is the primary key in the below table - u prefer? Village no shop no 100 1 100 2 101 1 101 2 8) how do u declare composite key in hibernate? 8)what is the difference between interface /abstractio(when do u use them). 9) which is more better approach (inf / abstrract) 10)what are Design patterns u know ? 11)String literal pool - String A="R"; A=A+"P"; What happens to string "R"(first initialization) - 12)public jre / private jre. 13)new features in 1.7 (only 1.7) 14)concurrent package. 15)Difference between ReEntrant lock and synchronized block. 16)any issues in project? - how u handeled? 17) how did u find which class has memory issue? 18)Why Map interface ? 19) sort Arralist od strings. 20) equals and hashcode? 21) comaparator's compare method does the comaprision on what objects? (ob1 and ob2???) 22)difference between session.get() and session.load() 23)Name the classes you have written in your project. 24) String A="ORACLE Financial Services" String B = "ORACLE"; find B in String A? 25) customized Exception? - have you written any? 26) can a abstract class be final? 27) why /what /how multithreading ?

how to run thread 1,thread 2, thread3 one after the other

Proxy Object in Hibernate?