Polish setSecurityContextHolderStrategy

Author: jzheaux

web/src/main/java/org/springframework/security/web/authentication/ui/DefaultLoginPageGeneratingFilter.java

@@ -123,7 +123,14 @@ private void initAuthFilter(UsernamePasswordAuthenticationFilter authFilter) {
 		}
 	}
 
+	/**
+	 * Use this {@link SecurityContextHolderStrategy} to retrieve authenticated users.
+	 * <p>Uses {@link SecurityContextHolder#getContextHolderStrategy()} by default.
+	 * @param securityContextHolderStrategy the strategy to use
+	 * @since 7.0
+	 */
 	public void setSecurityContextHolderStrategy(SecurityContextHolderStrategy securityContextHolderStrategy) {
+		Assert.notNull(securityContextHolderStrategy, "securityContextHolderStrategy cannot be null");
 		this.securityContextHolderStrategy = securityContextHolderStrategy;
 	}