---
title:  How Serialization Works with IDataSerializable
---

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When your application puts an object into the cache for distribution, <%=vars.product_name%> serializes the data by taking these steps.

1.  Calls the appropriate `ClassId` function and creates the `TypeId` from it.
2.  Writes the `TypeId` for the instance.
3.  Invokes the `ToData` function for the instance.

When your application subsequently receives a byte array, <%=vars.product_name%> takes the following steps:

1.  Decodes the `TypeId` and creates an object of the designated type, using the registered factory functions.
2.  Invokes the `FromData` function with input from the data stream.
3.  Decodes the data and then populates the data fields.

The `TypeId` is an integer of four bytes, which is a combination of `ClassId` integer and `0x27`, which is an indicator of user-defined type.