HCP 1.9.0 Release Notes
Also available as:

JDK Support Matrix

HCP 1.9.0 supports a select set of Java Development Kits (JDK) versions.

Unless otherwise noted, the following Java Development Kits (JDKs) are validated and supported for HDP 2.6.5:

Table 1. HDP 2.6.5 JDK Support Matrix
JDK Version
Open Source JDK8
Oracle JDK 8

Not validated, but supported.