On 04/19/2012 09:28 PM, Eyal Edri wrote: That test is serializing an object with Jackson and then manually, and comparing the result. It is failing because it gets this two things: Manually: {"integer":1992604070,"object":["org.ovirt.engine.core.compat.Guid",{"uuid":"7d47be2e-bc38-4d97-8489-21fcb316d799"}],"string":"\\VS|6BfM/!","guid":["org.ovirt.engine.core.compat.Guid",{"uuid":"cb15e87b-2878-4dcf-86e6-e388a32ff228"}]} Using Jackson: {"integer":1992604070,"guid":["org.ovirt.engine.core.compat.Guid",{"uuid":"cb15e87b-2878-4dcf-86e6-e388a32ff228"}],"string":"\\VS|6BfM/!","object":["org.ovirt.engine.core.compat.Guid",{"uuid":"7d47be2e-bc38-4d97-8489-21fcb316d799"}]} The only difference is the order of the fields. When generated manually the order is the one defined in the code, but when using Jackson the order depends on the internal ordering of the fields, and that can change between Jackson versions (we just updated to 1.9.4) or even when compiling with different compilers. The @JsonPropertyOrder annotation can be used like this to force the order: @JsonPropertyOrder({ "integer", "object", "string", "guid" }) public class JsonSerializablePojo implements Serializable { I am proposing this change to add the annotation so that the test will pass: http://gerrit.ovirt.org/3740