What is a boot.properties file and best usage?

"boot.properties" file is a property file which can be used to store properties of a server like username and password and other various credentials. In WebLogic, "boot.properties" file will be used to store username and password. When the Weblogic Server starts, say the Admin Server, it will take the credentials from the "boot.properties" file for authentication purpose and will encrypt it to prevent the user credentials from being exposed to the third person.
Every Server needs a "boot.properties" file. I have mentioned the steps to create a "boot.properties" file for the Admin Server and this procedure is the same for managed servers like SOA, BAM, IPM, UCM and etc...
STEPS:

1. You must have started the Admin Server or managed server atleast once.

2. Go to your $DOMAIN_HOME/Domain_directory/servers/<Name of your server>

eg: cd $MW_HOME/user_projects/domain/base_domain/servers/AdminServer

3. Create a folder called security and go to it

• command : mkdir security
• command : cd security

4. Create a file called "boot.properties"

• command : vi boot.properties

5. insert the following lines and save the file

username=<weblogic username>
password=<password which you entered while creating a domain>

example:

username = weblogicpassword = welcome1

6. Now try to start or restart the server via command prompt mode and you will notice that WebLogic has not prompted you for a username or password instead, it utilized the "boot.properties" file and if you try to see the "boot.properties" file, the username and password which you entered earlier have been encrypted.