How to access authentication alias from WebSphere Application Server> J2C

You can use the following code to obtain credentials from J2C authentication data entry:

import com.ibm.wsspi.security.auth.callback.Constants;
import com.ibm.wsspi.security.auth.callback.WSMappingCallbackHandlerFactory;
import javax.resource.spi.security.PasswordCredential;
import javax.security.auth.Subject;
import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.login.LoginContext;

Map map = new HashMap();
map.put(Constants.MAPPING_ALIAS, "YOUR_J2C_DATA_ALIAS");
CallbackHandler callbackHandler = WSMappingCallbackHandlerFactory.getInstance().getCallbackHandler(map, null);

LoginContext loginContext = new LoginContext("DefaultPrincipalMapping", callbackHandler);
loginContext.login();

Subject subject = loginContext.getSubject();
Set credentials = subject.getPrivateCredentials();

PasswordCredential passwordCredential = (PasswordCredential) credentials.iterator().next();

String user = passwordCredential.getUserName();
String password = new String(passwordCredential.getPassword());

Reference link: http://stackoverflow.com/questions/4663534/how-to-access-authentication-alias-from-ejb-deployed-to-websphere-6-1/6355992#6355992