Hierarchical Data Model In the Hierarchical data model, the relationship between the table and data is defined in parent-child structure. In this structure, data is arranged in the form of a tree structure. This model supports one-to-one and one-to-many relationships. Network Model The Network model arranges data in a graph ... Read More

SQL query is used to fetch data from the database. In some of the scenario you may need some perquisite data to call subsequent SQL query to fetch data from a table so instead of writing two seperate query we can write SQL query within the query. Therefore subQuery is a ... Read More

According to Oracle's Javadocs −Default methods enable you to add new functionality to the interfaces of your libraries and ensure binary compatibility with code written for older versions of those interfaces.A static method is a method that is associated with the class in which it is defined rather than with ... 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

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

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