Category: Java

  • Intro To iCal4J

    Intro To iCal4J

    Introduction Ben Fortuna\’s iCal4J library is a well-established Java implementation of the RFC 5545 international standard for calendar events. In this article I will show you how to use iCal4J to create a iCalendar event in Java and export it to a .ics file, and how to read in a .ics file and extract the…

  • Oauth2 SSO Keycloak Spring Security

    Oauth2 SSO Keycloak Spring Security

    Introduction In this article we will set up a Keycloak Oauth2 Single Sign-On (SSO) server with two clients and two user accounts with differing permissions. We will create a Spring Boot Java application (a \"resource server\") with two REST endpoints, secured by the Keycloak server and requiring different roles for access. We will send HTTP…

  • Java8 Path Filevisit Intro

    Java8 Path Filevisit Intro

    Goal of this Exercise In this article we will look at Java\’s SimpleFileVisitor as a tool to solve this problem: how to consolidate multiple backups of data, photos, and videos, from multiple devices such as phones and laptops. Suppose you (or your not-so-tech-savvy friends) use multiple devices and copy files between them, and edit different…

  • Java8 Date Time Intro

    Java8 Date Time Intro

    Why do you need to know about Java 8 date and time classes? In a lot of Java applications it is necessary to calculate business days, or manipulate dates for display or export: eg. calendar events. There is also a lot of old Java code which uses the old date and calendar classes, that needs…