How can I get the latest JRE / JDK as a zip file rather than EXE or MSI installer?

JDK is not available as a portable ZIP file, unfortunately. However, you can follow these steps:

• Create working JDK directory (C:\JDK in this case)
• Download latest version of JDK from Oracle (for example jdk-7u7-windows-x64.exe)
• Download and install 7-Zip (or download 7-Zip portable version if you are not administrator)
• With 7-Zip extract all the files from jdk-XuXX-windows-x64.exe into the directory C:\JDK
• Execute the following commands in cmd.exe:
  • cd C:\JDK\.rsrc\1033\JAVA_CAB10
  • extrac32 111
• Unpack C:\JDK\.rsrc\1033\JAVA_CAB10\tools.zip with 7-zip
• Execute the following commands in cmd.exe:
  • cd C:\JDK\.rsrc\1033\JAVA_CAB10\tools\
  • for /r %x in (*.pack) do .\bin\unpack200 -r "%x" "%~dx%~px%~nx.jar" (this will convert all .pack files into .jar files)
• Copy all contents of C:\JDK\.rsrc\1033\JAVA_CAB10\tools where you want your JDK to be
• Setup JAVA_HOME and PATH manually to point to your JDK dir and its BIN subdirectory.

• Create destination folder where you can RWX (e.g. C:\jdk8)
• Download jdk exe from Oracle (e.g. jdk-8u72-windows-x64.exe)
• Unzip the tools.zip found inside it into the destination folder
• In cmd.exe, run:
  • cd C:\jdk8
  • for /r %x in (*.pack) do .\bin\unpack200 -r "%x" "%~dx%~px%~nx.jar"

This solution works for JDK 8 too, without Admin rights.

You can download a Java Portable from PortableApps.com. It will not change your system settings. You can put it on your USB stick.

UPD: for those who needs JDK there's an open-source project OpenJDK Portable

UPD2: there is also a JDK Portable (Oracle)

Some people might be interested in official Oracle production-ready open source build of JDK