Assemble the collection of trusted CA certificates that you want to deploy. The trusted CA certificates can be obtained from public CAs or private CAs (for details of how to generate your own CA certificates, see Set Up Your Own CA). The trusted CA certificates can be in any format that is compatible with the Java keystore utility; for example, PEM format. All you need are the certificates themselves—the private keys and passwords are not required.

Given a CA certificate, cacert.pem, in PEM format, you can add the certificate to a JKS truststore (or create a new truststore) by entering the following command:

keytool -import -file cacert.pem -alias CAAlias -keystore truststore.ts -storepass StorePass 

Where CAAlias is a convenient tag that enables you to access this particular CA certificate using the keytool utility. The file, truststore.ts, is a keystore file containing CA certificates—if this file does not already exist, the keytool utility creates one. The StorePass password provides access to the keystore file, truststore.ts.

Repeat step 2 as necessary, to add all of the CA certificates to the truststore file, truststore.ts.