Roy Tutorials

Introduction In this post we will see how to set print area for excel sheet using apache poi in Java. There may be many number of columns and rows in your excel sheet but you need only few columns and rows to be printed in paper instead of all columns and rows from the sheet then you need to set…

Introduction We will create bootstrap calendar events demo using Python Flask MySQL. We had created similar example using Codeigniter (PHP framework) and MySQL. We will use the same version of bootsrap library 2.3.2 because using bootstrap version 4.3.1 the layout becomes a little messy. It helps users to track easily what all upcoming events are or past events were there…

Introduction Here I will discuss how to manage dependencies and plugins in multi module project using maven. A multi-module project is built from a parent pom that manages a group of sub-modules. In most of the cases, the parent pom is located in the parent project’s root directory and must have packaging of type pom. So in multi module project you…

Multiple Files Upload This example is about to upload multiple files using Python Flask REST API. You might have also seen how to upload single file using Python Flask REST API. You may need to upload single or multiple files according to application’s requirements and here I am going to create an example on Python Flask REST API multiple files…

Introduction Here you will see maven profile and non-profile based plugin execution. Situation may occur when you need to execute plugin(s) for different profile(s) and plugin(s) which do not need any profile for your application. For example, let’s say you want to copy some configuration files into some specific location for local environment where your application will be deployed and…

File Upload I will create here Python Flask REST API file upload example though you might have seen how to upload file using Python Flask in web application. You may need to upload a single file or multiple files into your application for a reason and here I am going to use light-weight web based Python framework called Flask to…

Introduction We will create an example where we fit excel sheet to one page using Apache POI in Java. Apache POI is a wonderful library for manipulating data into office documents, such as, excel, ppt, word etc. We will fit excel sheet to one page for the existing excel files – an excel file that contains only text as well…

Introduction In this post we will see how to secure REST API with JWT authentication using Python Flask. JWT is an acronym for JSON Web Token. In previous example we have seen how to secure REST API using HTTP Basic Authentication which is not recommended for most of the time. Recommended Reading REST API CRUD Example using Python Flask and…

Introduction In this post I will discuss about replacing the multiple tokens in XML file using maven-resources-plugin. Situation may occur where you need to replace some place holders in the XML file during build of your application and need to create a zip file under the target directory, then you may use this example as a reference. Such XML files…

I will tell you here what are the differences between Exception and Error in Java. There are mainly three important categories of Throwable: Error – something severe enough has gone wrong the most applications should crash rather than try to handle the problem. Unchecked Exception (also known as, RuntimeException) – mainly a programming error, such as, a NullPointerException or an…