I'm at that stage in application development where I'm forced to tinker with openssl and keytool again. I was surprised to find that I could list and export certs from a JKS key store without entering a password (although it printed a nifty little warning). So, I assume the sole purpose of the store password is to prevent illicit addition or replacement of certs and keys. The password on the keypair is what really protects the private key. Are these assumption correct?
The Password in the JKS file is used to protect the Private key file and also to maintain the integrity of the file. When your opening the file without password, you can able to export all certs but not the key and it will throw a warning as "integrity cannot be verified". And one more to be clear as the cert contains public key which is accessible to global and so need to protect that with password.