Memory Management How does the JVM divide memory on the heap?
What is the standard algorithm for garbage collection?
What are memory leaks? How can they be identified?
What are the four different types of references?
What is a ReferenceQueue?
Why is a phantom reference safer than using the finalize() method?
Java Database Connectivity
What is JDBC?
What are the two ways of acquiring a Connection object?
What is the difference between the three types of Statements?
What is a ResultSet?
What is an SQL injection attack? How can it be prevented?
What are the advantages and disadvantages of object-relational mapping?
What is Hibernate?
Web Applications What is a servlet container?
What is a web application?
What is a WAR file?
What is a web.xml file?
What is the difference between a Servlet and an HttpServlet?
What is the difference between a Servlet and a JSP?
What is a servlet filter?
What is the model-view-controller pattern?
Web Services
What is service-oriented architecture?
What are web services?
What is the difference between a SOAP web service and a REST web service?
What is the difference between JAX-WS and JAX-RS?
What are some frameworks that aid in the development of Java web services?
Algorithms What is Big O notation? What are some common examples?
What is a binary search? How well does it perform?
What is insertion sort? How well does it perform?
What is merge sort? How well does it perform?
What is quicksort? How well does it perform?
What is timsort? How well does it perform?
Java Collections Framework What is the difference between an ArrayList and a LinkedList?
How does a HashMap work internally?
What would happen if a key’s hashCode() or equals() method was incorrect?
What is the difference between a stack and a queue?
What is the difference between a binary search tree, red-black tree, and a heap?
What is the difference between a HashSet, LinkedHashSet, and TreeSet?
What is the difference between a fail-fast iterator and a fail-safe iterator?