If you are interested in learning about design Pattern,then please visit the link

 https://premaseem.wordpress.com/category/computers/design-patterns/

I have also included the source code in java while explaining each design pattern. If you want to have a look at java code then feel free to download the working example demo code in java from my GIT repository –
https://github.com/premaseem/designPatterns/tree/master/ZipDownloadableProjects