hCentive Java Interview Questions

What do you understand by thread-safety ? What are various mechanisms to achieve thread-safety in java ?

How will you design your own ReentrantReadWriteLock class where one thread can write and many threads can read in parallel ? How does it affect the throughput of a multi-threaded system ?

What are various methods to acquire lock in java ? discuss their comparison.

How to avoid deadlock in your application ?

How is ConcurrentHashMap better than hashmap in java ?

What are different memory generations in Java ? What is Stack and heap memory ?

Write a thread-safe Singleton Java Class.

What is difference between hashtable, hashmap and Concurrenthashmap in java ?

What is difference between Iterator and ListIterator in Java ?

What is Immutable Class ? What is reason behind using a Immutable class in your application ?

What is difference between String, StringBuffer and StringBuilder ?

What is difference between CheckedException and UncheckedException ? Give some example of RuntimeException ?

What are different Bean scopes in Spring ? What is the default bean scope ?

How many objects Spring container creates for a given bean definition ?

What is Bean Lifecyle ?

How do you encrypt a password in spring security ?

Describe practical use of Spring Interceptors ?

What is Servlet LifeCycle ?

How do you declare a custom error page in Spring ?

What is difference between doGet() and doPost() methods ?

What is difference between Forward and Redirect ?