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Any properties not found in an installation's cdap-site.xml will use a default parameter value defined in the file cdap-default.xml. It is located in the CDAP JARs and should not be altered.
You can find all of the available parameters in CDAP git:
https://github.com/cdapio/cdap/blob/release/<version>/cdap-common/src/main/resources/cdap-default.xml
For example, to see all of the available parameters in CDAP 6.7.x: https://github.com/cdapio/cdap/blob/release/6.7/cdap-common/src/main/resources/cdap-default.xml
Any of the default values (with the exception of those marked [Final]) can be overridden by defining a modifying value in the cdap-site.xml file, located (by default) either in <CDAP-HOME>/conf/cdap-site.xml (CDAP Sandbox) or /etc/cdap/conf/cdap-site.xml (Distributed CDAP).
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