The launcher's java download is broken due to oracle's recent change to their licencing policy. They require a sign in now. I don't know when that will be amended in the launcher, if ever.
If it is stuck on extracting, you need to download it yourself from
here. Make 100% sure you download jre 8.1.* 64bit.
Next, open the launcher, click the gear icon, go to 'Java' and make sure the Java Executable path points at wherever you just installed it. By default, windows installs it at C:\Program Files\Java\... It needs to point at a javaw.exe