AntiBlitz wrote:instead of attempting to explain something thats somewhat technical.
None of this works if Java isn't installed first. The only time that a .jar file isn't opened when double-clicked is if Java isn't installed or the path isn't properly configured.
Download Java from
https://www.java.com/en/download/manual.jsp Get the appropriate 64-bit version for Windows. (Most people are still running 32-bit browsers, and this is what is detected for the "appropriate download" for the operating system if you allow java.com to auto-detect the download for your computer.)
Already installed Java? It may not be finding the proper executable to run a .jar file. Simply "Run with" and select Java as the appropriate application. If you don't see it there, you can browse to the location you installed java (typically c:\Windows\Program Files(x86)\java_<ver_num>), and look in the "bin" folder for "java.exe".
As far as the modded and custom client, Amber, Ender's, Puru's Pasta, and Ardenne's clients are accepted by the community as reliable.
Opinions expressed in this statement are the authors alone and in no way reflect on the game development values of the actual developers.