Basics of ClassLoaders in Java

The Classloaders in Java dynamically load Java classes into the Java Virtual Machine. Usually classes are only loaded on demand. By default, Java uses three class loaders, when JVM starts. Bootstrap classloader Extension classloader System classloader Following figure shows the role of each ClassLoader:- The ClassLoaders in Java works on…

Continue reading

Writing a Simple Java Program

Here we will write a simple program in Java. Pre-requisites :- Java installed on your system. Download Java JDK and add JAVA_HOME environment variable to your system. Add ‘JAVA_HOME/bin’ path to your system’s PATH variable. IDE for Java- like eclipse. Assuming that you are done with the above requirements. Lets…

Continue reading

Creating and accessing Encrypted database in OrientDB using the graph APIs

OrientDB supports encrypting database content to prevent unauthorized users from accessing the data. The encryption support is available from version 2.2. To create/access an encrypted database, we need to provide a base64 encoded encryption key. OrientDB supports encryption at a database level and each database can be encrypted with different…

Continue reading

Comparison of Storage formats in Hive – TEXTFILE vs ORC vs PARQUET

We will compare the different storage formats available in Hive. The comparison will be based on the size of the  data on HDFS and time for executing a simple query. Cluster summary The performance is bench marked using a 5 node Hadoop cluster. Each node is a 8 core, 8…

Continue reading