open command line and locate to the location of keytool.exe.
import cert to keystore command:
keytool -importkeystore -srckeystore %certfileName% -srcstoretype PKCS12 -srcstorepass %CertFilePassword% -keystore %Thekeystore file that the cert will import to% -storepass %Thepassword will be used to read from keystore file.% -srcalias 1 -destalias %TheAliasNameUsedInKeystore file%
sample:
C:Program FilesJavajre1.8.0_91in>keytool.exe -importkeystore -srckeystore C:MediaFirstGetToken v3certossPerfA.pfx -srcstoretype PKCS12 -srcstorepass password -keystore C:MediaFirstToosJMRunnerConfigsMediaFirstApiTest.keystore -storepass password -srcalias 1 -destalias MediaFirstScale