Programming always take too much time of programming. So here are a few tips which can help programmers to programming fast and easy. There are many Java programming files with .java extensions which can copy from one folder to another folder on PC. We can easily change that.Java extension in other extension we want. Just like a.Text files. This type of program takes just two input parameters. Source directory and target directory are two input parameters of the program. Also the program displays sometimes an error.