Java 8 is the latest release for Java that contains new features, enhancements and bug fixes to improve efficiency to develop and run Java programs.
The new release of Java is first made available to developers to give adequate time for testing and certification before being made available on the java.com website for end users to download. If you are interested in trying Java 8 it can be downloaded from Oracle.com.
Java 8 is expected to be the default Java runtime on java.com before the end of 2014, and the process of migrating users from Java 7 to Java 8 through the auto update feature to take place during the first half of 2015.
Some application providers might require that you use a particular Java release and have not certified their applications with Java 8. If you experience problems running an application with Java 8, check with your application provider and confirm that it is certified with this version.
As of April 8, 2014 Microsoft stopped supporting Windows XP and therefore it is no longer a supported platform. XP users will be unable to install Java 8. Windows users must upgrade to Windows Vista or later to install Java 8.
See Third Party Vendor-Specific Support Terms on Oracle Software Technical Support Policies (pdf) for details.