In this post we will see how to upload a multipart file using Spark Java. We will have a HTML frontend where user will select a file from his/her system. Then pressing the "Upload" button the file will be posted as multipart data to server. In the server side, the multipart file will be fetched and saved to a …

In this example, we will see how to build a simple web application in Spring boot with Thymeleaf as template engine and H2 database as embedded or in-memory database. Gradle has been used as build and dependency management tool. We will create a sample Student Information System where we can enter Student record in one …

The CrudRepository interface provides the CRUD functionality in Spring JPA. It comes with default definitions of methods to execute common operations like find, save and delete records. To work with a domain class, we need to inherit the CrudRepository to create a new interface corresponding to the domain class. Here …

1. Join list of strings using Java 8 String.join(...) If we use Java 8, it is very easy to join a list or array of strings using a delimiter. For a common situation like building a CSV line, this approach is very easy and straightforward. 1List<String> stringList = new ArrayList<>(); …

This post is very similar with the Spark Java example with JQuery Ajax except here we would use POST method for the Ajax call. Like the other example, we would get input of two numbers from the web page UI, make a ajax POST call to server with those numbers, the numbers get added at the server and returned result and …

In Java, the TreeSet is a special implementation of Set interface to store unique objects in sorted order. By default it stores the objects in ascending order by performing simple compare. There are couple of ways to use the TreeSet as per our requirement. Here we would discuss about few most commonly used ways. First …

Spark is a relatively new, simple and lightweight framework written in Java which helps developers to rapidly create web services in minimal effort. It comes with embedded Jetty web server which hosts the web services. The syntax of declaring web services are very simple, quite similar with Node.js, which makes Node.js …

There are few open source libraries available to extract files from Zip archive. Apache common compress is one of the popular library. We can use gradle to resolve the dependency of Apache common compress. For this, we have to make an entry under dependency in build.gradle like this: 1dependencies { 2 compile …

JQuery made it really simple working with HTML select control. Consider you have following select control and you want to do various operations as listed thereafter. 1<select id="selectCtrl" multiple="multiple"> 2 <option value="bb">Black Berry</option> 3</select> The …

Abstract class is such a class where It is not possible to instantiate object from it It is meant for deriving other classes from it It is used as a type It is declared with abstract keyword An abstract class typically contains one or more abstract methods. Although it is not mandatory to have abstract methods at …