hibernate - @GeneratedValue(strategy = GenerationType.AUTO) not working as thought -

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i'm trying persist object database. keep getting 'column id cannot accept null value error'. object looks this:

    @entity public class testtable {     @id     @generatedvalue(strategy = generationtype.auto)     private integer id = 0;      @column(nullable=false, length=256)     private string data = "";      public integer getid() {         return id;     }      public void setid(integer id) {         this.id = id;     }      public string getdata() {         return data;     }      public void setdata(string data) {         this.data = data;     }  }

my persist function: 

public static synchronized boolean persistobject(object obj){         boolean success = true;         entitymanager em = null;         entitytransaction tx = null;         try{             em = getemf().createentitymanager();             tx = em.gettransaction();             tx.begin();             em.persist(obj);             tx.commit();          } catch (exception e){             success = false;         } finally{             try{                 em.close();             } catch(exception e){                 //nothing             }         }         return success;     }

you may use generationtype.table. way, jpa uses sequence table id assigment , may never need generate sequence or auto-increment values or triggers lowers portability.

also note in java int type initiated 0 default, may rid of also.


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