What is the use of J2C alias on WAS server? - spring

Question

This is my LdapTemplate Class
public LdapTemplate getLdapTemplete(String ldapID)
{
if (ldapID.equalsIgnoreCase(Constants.LDAP1))
{
if (ldapTemplate1 == null)
{
try
{
PasswordCredential passwordCredential = j2cAliasUtility.getAliasDetails(ldapID);
String managerDN = passwordCredential.getUserName();
String managerPwd = new String(passwordCredential.getPassword());
log.info("managerDN :"+managerDN+":: password : "+managerPwd);
LdapContextSource lcs = new LdapContextSource();
lcs.setUrl(ldapUrl1);
lcs.setUserDn(managerDN);
lcs.setPassword(managerPwd);
lcs.setDirObjectFactory(DefaultDirObjectFactory.class);
lcs.afterPropertiesSet();
ldapTemplate1 = new LdapTemplate(lcs);
log.info("ldap1 configured");
return ldapTemplate1;
}
catch (Exception e)
{
log.error("ldapContextCreater / getLdapTemplete / ldap2");
log.error("Error in getting ldap context", e);
}
}
return ldapTemplate1;
}
This is my J2CAliasUtility Class--I dont know what is this method doing and what does it return ?
public PasswordCredential getAliasDetails(String aliasName) throws Exception
{
PasswordCredential result = null;
try
{
// ----------WAS 6 change -------------
Map map = new HashMap();
map.put(com.ibm.wsspi.security.auth.callback.Constants.MAPPING_ALIAS, aliasName); //{com.ibm.mapping.authDataAlias=ldap1}
CallbackHandler cbh = (WSMappingCallbackHandlerFactory.getInstance()).getCallbackHandler(map, null);
LoginContext lc = new LoginContext("DefaultPrincipalMapping", cbh);
lc.login();
javax.security.auth.Subject subject = lc.getSubject();
java.util.Set creds = subject.getPrivateCredentials();
result = (PasswordCredential) creds.toArray()[0];
}
catch (Exception e)
{
log.info("APPLICATION ERROR: cannot load credentials for j2calias = " + aliasName);
log.error(" "+e);
throw new RuntimeException("Unable to get credentials");
}
return result;
}

Answer 1

J2C alias is a feature that encrypts the password used by the adapter to access the database. The adapter can use it to connect to the database instead of using a user ID and password stored in an adapter property.
J2C alias eliminates the need to store the password in clear text in an adapter configuration property, where it might be visible to others.

Answer 2

It would seem that your class "J2CAliasUtility" retrieves a user name and password from an JAAS (Java Authentication and Authorization Service) authentication alias, in this case apparently looked-up from LDAP. An auth alias may be configured in WebSphere Application Server as described here and here. Your code uses WebSphere security APIs to retrieve the user id and password from the given alias. More details on the programmatic logins and JAAS made be found in this IBM KnowledgeCenter topic and it's related topics.