OpenJDK 64-Bit Server VM, Java 1.7.0_101 is used in HDP-2.5.
JDK 1.7 is used for HDP 2.5 Sandbox. However there is also a JDK 1.8 in the Sandbox but that is used for NiFi 1.0. In the future the HDP Sandbox will be moving to JDK 1.8. @rmolina @glupu
HDF 2.0 and NiFi 1.0.0 using JDK 1.8. JDK 1.7 is deprecated by Oracle, so for your own installs, make sure you pick the latest JDK 1.8