http://artemgolubev.com Thoughts on software Tue, 20 Apr 2010 18:20:37 +0000 http://wordpress.org/?v=2.8.2 en hourly 1 http://artemgolubev.com/algorithm-for-generating-serialversionuid-for-java-entities/ http://artemgolubev.com/algorithm-for-generating-serialversionuid-for-java-entities/#comments Mon, 24 Mar 2008 03:32:11 +0000 Artem http://artemgolubev.com/algorithm-for-generating-serialversionuid-for-java-entities/ Here is some way of generating serialVersionUID for java entities.
It is stable in sense that it depends only on your schema, not JVM/time or date of creation.
On the other hand it depends on all fields in entity. If we have next n fields:
typeName_1 fieldName_1;
typeName_2 fieldName_2;
…
typeName_n fieldName_n;we could calculate
serialVersionUID =
(fieldName_1.hashCode() XOR typeName_1.hashCode()) * 31^0+
(fieldName_2.hashCode() XOR typeName_2.hashCode()) * 31^1 + … +
(fieldName_n.hashCode() XOR typeName_n.hashCode()) * 31^n where fieldName_i.hashCode() is hashCode() of fieldName_i string
(for int id; it will be “id”.hashCode())
and typeName_i.hashCode() is hashCode() of typeName_i string
(for int id; it will be “int”.hashCode())so, we will be independent from
1) JVM
2) time/date of creation
and depend on
1) fields order
2) field types
3) field names

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