Concurrent Hashmap is a class that was introduced in jdk1.5.  Concurrent hash map applies locks only at bucket level called fragment while adding or updating the map. So, a concurrent hash map allows concurrent read and write operations to the map. HashTable is a thread-safe legacy class introduced in the Jdk1.1. ... Read More

Oracle 12c is just upgraded version of the Oracle 11g with some new features like cloud support and pluggable database, kind of like master slave architecture. With the Oracle 12 c, you can plug your database to cloud anytime. It has multiple new features like JSON support, multitenant architecture and ... Read More

Ant and maven both are build tools.They both can be used for compile, pulling dependence from repository and for creating war or ear files. Both are provided by the Apache.Ant is a tool and it doesn't have formal conventions. If you are using Ant then you have to tell what ... Read More

Hibernate and Eclipse link both are object relational mapping tool. They both are the implementation of JPA.Hibernate is very popular implementation of JPA built by Red hat. It also has some extra features that JPA does not provide.Eclipse is an open source implementation of JPA built by Eclipse foundation. It ... Read More

String is an immutable class and its object can’t be modified after it is created but definitely reference other objects. They are very useful in multithreading environment because multiple threads can’t change the state of the object so immutable objects are thread safe.String buffer is mutable classes which can be ... Read More

Polymorphism is one of the most important OOPs concepts. Its is a concept by which we can perform single task in multiple ways. There are two types of polymorphism one is Compile-time polymorphism and another is run-time polymorphism.Method overloading is the example of compile time polymorphism and  method overriding is ... Read More

In Java, state of the immutable object can’t be modified after it is created b ut definitely reference other objects. They are very useful in multithreading environment because multiple threads can’t change the state of the object so immutable objects are thread safe. Immutable objects are very helpful to avoid ... Read More

CountDownLatch and CyclicBarrier both used in multithreading environment and they both are part of.As per Java Doc −CountDownLatch − A synchronization aid that allows one or more threads to wait until a set of operations being performed in other threads completes.CyclicBarrier − A synchronization aid that allows a set of ... Read More

Docker Swarm and Kubernetes both can be used for similar purpose. They both are container orchestration tool.Docker Swarm is a tool used for clustering and scheduling Docker containers. We can easily establish and manage a cluster of Docker nodes under a single virtual system.Kubernetes is also container orchestration tool which ... Read More

Kafka and JMS both are messaging system. Java message service is an api which are provided by Java. It is used for implementing messaging system in your application. JMS supports queue and publisher /subscriber(topic) messaging system . With queues, when first consumer consumes a message, message gets deleted from the ... Read More