Apache Cassandra

Apache Cassandra is a highly scalable, high-performance distributed database designed to handle large amounts of data across many commodity servers, providing high availability with no single point of failure. It is a type of NoSQL database.

Cassandra provides a prompt Cassandra query language shell (cqlsh) that allows users to communicate with it. Using this shell, you can execute Cassandra Query Language (CQL).

Using cqlsh, you can

• define a schema,
• insert data, and
• execute a query.

Commands

cqlsh

describe keyspaces

Used Python 2.7 because apache-cassandra-3.11.8 uses it.

Ctrl + C - to stop server

Start Cassandra 

goto cmd type cassandra 

Difference between Collection and Collections ?

Collection is an interface whereas Collections is a utility class in Java.

List, Queue, Set are subinterfaces of collection interface. Map is also part of the collection framework.

The important methods used in collection interface are add(), remove(), size(), clear.

Collections class consists of only static methods like min(), max(), sort(), reverse(), synchronizedMap().

Collections.sort()

Dependency Injection (DI)

Dependency Injection is a technique in which an object receives other objects that it depends on. These other objects are called dependencies.

Inversion of Control (IoC)

 What is IoC?

Inversion of Control is a principle by which the control of objects or portions of a program is transferred to a container or framework.

CMD commands

cls  - to clear screen

start . 

code . 

Print environment variables

echo %JAVA_HOME%

echo %PATH%