GemFire XD policy is to support JDK versions for one year past their end-of-life (EOL). Oracle (formerly Sun) JDK 1.6 entered end-of-life in April 2013. In line with end-of-life of the 1.6 JDK by Oracle, GemFire XD 1.4 drops support for Oracle JDK version 1.6.
Resolution
Customers installing GemFire XD 1.4 or later will need to upgrade to a JDK 1.7 runtime as part of installation. GemFire does not ship with a JRE so the end user is expected to download the runtime (available independently and as part of the 1.7 JDK) in order to use the newer product version.