web/src/main/java/org/springframework/security/web/authentication/preauth/j2ee/J2eePreAuthenticatedProcessingFilter.java
protected Object getPreAuthenticatedPrincipal(HttpServletRequest httpRequest) {
		Object principal = httpRequest.getUserPrincipal() == null ? null : httpRequest
				.getUserPrincipal().getName();
		if (logger.isDebugEnabled()) {
			logger.debug("PreAuthenticated J2EE principal: " + principal);
		}
		return principal;
	}
protected Object getPreAuthenticatedPrincipal(HttpServletRequest httpRequest) {
		Object principal = httpRequest.getUserPrincipal() == null ? null : httpRequest
				.getUserPrincipal().getName();
		if (logger.isDebugEnabled()) {
			logger.debug("PreAuthenticated J2EE principal: " + principal);
		}
		return principal;
	}
Return the J2EE user name.