Java SE considerations

WebSphere® eXtreme Scale requires Java™ SE. In general, newer versions of Java SE have better functionality and performance.

Supported versions

You can use WebSphere eXtreme Scale with Java SE Version 7. The version that you use must be currently supported by the Java Runtime Environment (JRE) vendor. If you want to use Secure Sockets Layer (SSL), you must use an IBM® Runtime Environment.

IBM Runtime Environment, Java Technology Edition Version 7 is supported for general use with the product. If you are installing WebSphere eXtreme Scale within WebSphere Application Server, you can use the JRE that is included in the WebSphere Application Server installation.

WebSphere eXtreme Scale takes advantage of Java Development Kit (JDK) Version 7 functionality as it becomes available. Generally, newer versions of the Java Development Kit (JDK) and Java SE have better performance and functionality.

For more information, see Supported software.

WebSphere eXtreme Scale features that are dependent on Java SE

Table 1. Features that require Java SE 7. WebSphere eXtreme Scale uses functionality that is introduced in Java SE 6 to provide the following product features.
Feature	Supported in Java SE 5 and later service releases Note: Java SE 5 is not supported in WebSphere eXtreme Scale Version 8.6 and Version 8.6.1	Supported in Java SE Version 6 , Version 7 and later service releases
EntityManager API annotations (Optional: You can also use XML files)	X	X
Java Persistence API (JPA): JPA loader, JPA client loader, and JPA time-based updater	X	X
Memory-based eviction (uses MemoryPoolMXBean)	X	X
Instrumentation agents: wxssizeagent.jar: Increases the accuracy of the used bytes map metrics. ogagent.jar: Increases the performance of field-access entities.	X	X
Web console for monitoring		X

Upgrading the JDK in WebSphere eXtreme Scale

Common questions about the upgrade process for releases of WebSphere eXtreme Scale in both stand-alone and WebSphere Application Server environments follow:

How do I upgrade the JDK that is included with WebSphere eXtreme Scale for WebSphere Application Server?
You need to use the JDK upgrade process that is made available by WebSphere Application Server. For more information, see http://www-304.ibm.com/support/docview.wss?uid=swg21427178.
Which version of the JDK should I use when using WebSphere eXtreme Scale in a WebSphere Application Server environment?
You can use any level of JDK that is supported by WebSphere Application Server, for the supported version of WebSphere Application Server.