core/src/main/java/org/springframework/security/authentication/jaas/SecurityContextLoginModule.java
public boolean commit() throws LoginException {
		if (authen == null) {
			return false;
		}

		subject.getPrincipals().add(authen);

		return true;
	}
public boolean commit() throws LoginException {
		if (authen == null) {
			return false;
		}

		subject.getPrincipals().add(authen);

		return true;
	}
Authenticate the <code>Subject</code> (phase two) by adding the Spring Security
<code>Authentication</code> to the <code>Subject</code>'s principals.

@return true if this method succeeded, or false if this <code>LoginModule</code>
should be ignored.

@exception LoginException if the commit fails