To generate a new private key with alias and store it in file KEYSTORE_NAME
keytool -genkey -alias MYALIAS -keystore KEYSTORE_NAME
Generate a temporary certificate file
keytool -export -alias MYALIAS -file certfile.cer -keystore KEYSTORE_NAME
To make a Certificate Signing Request(CSR) from existing JAVA Keystore
keytool -certreq -alias MYALIAS -keystore KEYSTORE_NAME -file MYALIAS.csr
To see list of alias in current keystore
keytool -list -keystore KEYSTORE_NAME
References: