keycloak/docs/documentation/server_development/topics/preface.adoc

== Preface

=== Container Images

The official {project_name} container image uses OpenJDK {jdk_version_recommended} as the Java runtime environment.
Consider this when writing custom extensions.

=== Example Listings

In some of the example listings, what is meant to be displayed on one line does not fit inside the available page width. These lines have been broken up. A '\' at the end of a line means that a break has been introduced to fit in the page, with the following lines indented.
So:

[source]
----
Let's pretend to have an extremely \
  long line that \
  does not fit
This one is short
----
Is really:

[source]
----
Let's pretend to have an extremely long line that does not fit
This one is short
----