Import .p12 file into .jks (assuming the .p12 has a password)

If it doesn't have a passwod use previous post to add one first.

Obtain the name of the alias for the tomcat key in the certificate file using the following command:
keytool -v -list -storetype pkcs12 -keystore FILE_PFX

Next plug in the source file, alias name, new .jks file name keystore password and new alias into this command:
keytool -importkeystore -srckeystore [MY_FILE.p12] -srcstoretype pkcs12
-srcalias [ALIAS_SRC] -destkeystore [MY_KEYSTORE.jks]
-deststoretype jks -deststorepass [PASSWORD_JKS] -destalias [ALIAS_DEST]