Future Methods Limitations

Hi

Below are the list of the limitations for future annotation.

• Methods with the future annotation must be static methods, and can only return a void type.

• The specified parameters must be primitive data types, arrays of primitive data types, or collections of primitive data types. 

• Methods with the future annotation cannot take sObjects or objects as arguments.

• Remember that any method using the future annotation requires special consideration because the method does not necessarily execute in the same order it is called.

• Methods with the future annotation cannot be used in Visualforce controllers in either getMethodName or setMethodName methods, nor in the constructor.

 

• You cannot call a method annotated with future from a method that also has the future annotation. Nor can you call a trigger from an annotated method that calls another annotated method.

• The getContent and getContentAsPDFPageReference methods cannot be used in methods with the future annotation. 

For more information please refer the below link.

https://www.salesforce.com/us/developer/docs/apexcode/Content/apex_classes_annotation_future.htm