As a Java developer sometimes I need a version of Java Development Kit (JDK) that is not the one installed on my PC. Oracle Java installer on Windows does too many things that I cannot control (like changing the JVM used by browsers to run applets). As of this writing Java 8 is not yet available for general consumption but you can get an early access release here.
Open the downloaded file with 7-zip and then open the tools.zip you find inside. Extract everything to a convenient path like C:\jdk-1.8-ea.
Now it is shell time so open a DOS console (Start->Run…->cmd) and type:
Create a portable JDK 1.8
> cd C:\jdk-1.8-ea
> for /r %x in (*.pack)do C:\jdk-1.8-ea\bin\unpack200 "%x""%x.jar"
Now you are almost done but you need to rename some files: