[SalesForce] System.SObjectException: Invalid relationship name for Lead

With the Callable interface that was introduced in Winter '19 you can now build a light weight interface for the methods you want to dynamically call from a class.

The example below is from the docs (tweaked to show dynamic method naming):

Example class you want to dynamically call

public class Extension implements Callable {

   // Actual method
   String concatStrings(String stringValue) {
     return stringValue + stringValue;
   }

   // Actual method
   Decimal multiplyNumbers(Decimal decimalValue) {
     return decimalValue * decimalValue;
   }

   // Dispatch actual methods
   public Object call(String action, Map<String, Object> args) {
     switch on action {
       when 'concatStrings' {
         return this.concatStrings((String)args.get('stringValue'));
       }
       when 'multiplyNumbers' {
         return this.multiplyNumbers((Decimal)args.get('decimalValue'));
       }
       when else {
        throw new ExtensionMalformedCallException('Method not implemented');
       }
     }
   }

   public class ExtensionMalformedCallException extends Exception {}
}

Unit test demonstrating the dynamic calling

@IsTest
private with sharing class ExtensionCaller {

   @IsTest
   private static void givenConfiguredExtensionWhenCalledThenValidResult() {

      // Given
      String className = 'Extension'; // Variable to demonstrate setting class name
      String methodName = 'multiplyNumbers'; // Variable to demonstrate setting method name
      Decimal decimalTestValue = 10;

      // When
      Callable extension = (Callable) Type.forName(className).newInstance();
      Decimal result = (Decimal) extension.call(methodName, new Map<String, Object> { 'decimalValue' => decimalTestValue });

      // Then
      System.assertEquals(100, result);
   }
}

I have used cookies in the past, and struggled in the same way that you did. My understanding of the constructor is as follows:

Cookie cook=new Cookie('Name', 'Keir Bowden', null, 1440, false);

Where:

• 'Name' = the name of the cookie
• 'Keir Bowden' = the value of the cookie
• null = the cookie path (where null results in the default location '/')
• 1440 = the max age
• false = is the cookie only accessible through https

Pretty sure I found this through trial and error and inspecting the HTTP messages - its still my opinion though!

I also recall that the max age didn't seem to have any effect, and I could only generate session cookies, but in the end I couldn't do what I wanted to anyway so I didn't investigate further.