The following seems to work.
KeyStore ks = KeyStore.getInstance("PKCS12");
FileInputStream fis = new FileInputStream("certFileName");
ks.load(fis, "password".toCharArray());
Enumeration aliasEnum = ks.aliases();
Key key = null;
Certificate cert = null;
while(aliasEnum.hasMoreElements()){
String keyName = (String)aliasEnum.nextElement();
key = ks.getKey(keyName,"password".toCharArray());
cert = ks.getCertificate(keyName);
}
KeyPair kp = new KeyPair(cert.getPublicKey(),(PrivateKey)key);