web/src/main/java/org/springframework/security/web/authentication/AbstractAuthenticationTargetUrlRequestHandler.java
public void setTargetUrlParameter(String targetUrlParameter) {
		if (targetUrlParameter != null) {
			Assert.hasText(targetUrlParameter, "targetUrlParameter cannot be empty");
		}
		this.targetUrlParameter = targetUrlParameter;
	}
public void setTargetUrlParameter(String targetUrlParameter) {
		if (targetUrlParameter != null) {
			Assert.hasText(targetUrlParameter, "targetUrlParameter cannot be empty");
		}
		this.targetUrlParameter = targetUrlParameter;
	}
If this property is set, the current request will be checked for this a parameter
with this name and the value used as the target URL if present.

@param targetUrlParameter the name of the parameter containing the encoded target
URL. Defaults to null.