Do I need to install Java to use Reaxys?

If you use New Reaxys (https://new.reaxys.com) then you don't have to install Java.

New Reaxys only supports Java-free structure editors like Marvin JS due to all modern browsers limiting Java-based codes for security reasons. Google Chrome didn’t support Java from the beginning and recently Firefox too has been limiting support, with only a special Extended Support Release version offering it now. More information can be found on the Java website.