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

		subject.getPrincipals().remove(authen);
		authen = null;

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

		subject.getPrincipals().remove(authen);
		authen = null;

		return true;
	}
Log out the <code>Subject</code>.

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

@exception LoginException if the logout fails