Good Study pages

Here are Some wonderful study sites:

    Freshers:

                 Java Understanding

                 Java and Data Structures
       
                 Technical Interview Questions and Answers

                 GATE preparations

    Experienced: 

                Design Patterns for Object Oriented Programming

                Oracle SQL practical Questions

               Performance tuning in Oracle

     Big Product Companies like Amazon , Microsoft , Oracle , Facebook:

               Note that these companies will ask Algos and DS for all most all job levels

                Algorithms and Data Structures Question

                Java and Hadoop interview questions