web/src/main/java/org/springframework/security/web/savedrequest/SavedRequestAwareWrapper.java
@Override
	public String getParameter(String name) {
		String value = super.getParameter(name);

		if (value != null) {
			return value;
		}

		String[] values = savedRequest.getParameterValues(name);

		if (values == null || values.length == 0) {
			return null;
		}

		return values[0];
	}
@Override
	public String getParameter(String name) {
		String value = super.getParameter(name);

		if (value != null) {
			return value;
		}

		String[] values = savedRequest.getParameterValues(name);

		if (values == null || values.length == 0) {
			return null;
		}

		return values[0];
	}
If the parameter is available from the wrapped request then the request has been
forwarded/included to a URL with parameters, either supplementing or overriding the
saved request values.
<p>
In this case, the value from the wrapped request should be used.
<p>
If the value from the wrapped request is null, an attempt will be made to retrieve
the parameter from the saved request.