i want to know alot about object oriented programming in java,please guyz suggest me a book that would guide me write big programs that can encounter problems in our daily life for example transport,health services,social services etc.
I strongly recommend the Head First series. For starting with OOP in Java, you can try "Head First Java", by Sierra and Bates (http/amzn.com/0596009208). Plenty of examples given, analogies with real life situations etc. Once you understand the basics, if you want to get into details, then try Horstmann C., Cornell G. - Core Java (2 volumes).