GemFire 7 and later
The purpose of this article os to explain the limits in String length when using PDX serialization.
GemFire PDX serialization does not directly limit the length of a String. So any String that can be created in Java can be serialized.
But note that PDX serialization poses another limit that can in theory have impact. Each object that is serialized with PDX has a 2GB limit to its total serialized size that includes nested objects. This is because the PDX header records the serialized length of the object bytes as a signed 32bit int