A certificate management utility included with Java.
Create a keystore
keytool -genkeypair -v -keystore path/to/file.keystore -alias key_name
Change a keystore password
keytool -storepasswd -keystore path/to/file.keystore
Change a key's password inside a specific keystore
keytool -keypasswd -alias key_name -keystore path/to/file.keystore