Serializing Java objects into Oracle blob columns sometimes results in corrupted data -

i use serialization save objects oracle blob columns extract , use in same run or in other runs.

the serialization/deserialization looks this:

public final class bytestransformer {  static bytestransformer btinstance = new bytestransformer(); private bytearrayoutputstream bytesoutputstream = new bytearrayoutputstream(); private objectoutputstream objectoutputstream; private bytearrayinputstream bytesinputstream; private objectinputstream objectinputstream;  public static bytestransformer getinstance() {     return btinstance; }  private void initialiseinputstreams(byte[] bytes) throws ioexception {     bytesinputstream = new bytearrayinputstream(bytes);     objectinputstream = new objectinputstream(bytesinputstream); }  private void initialiseinputstreams(inputstream bytes) throws ioexception {     objectinputstream = new objectinputstream(bytes); }  public byte[] getbytes(serializable sobject) throws ioexception {     bytesoutputstream.reset();     objectoutputstream = new objectoutputstream(bytesoutputstream);     objectoutputstream.writeobject(sobject);     objectoutputstream.close();      return bytesoutputstream.tobytearray(); }  public object frombytes(byte[] databytes) throws ioexception, classnotfoundexception {     initialiseinputstreams(databytes);     object sobject = objectinputstream.readobject();     closeinputstreams();     return sobject; }  public object frombytes(inputstream databytes) throws ioexception, classnotfoundexception {     initialiseinputstreams(databytes);     object sobject = objectinputstream.readobject();     closeinputstreams();     return sobject; }  private void closeinputstreams() {     try {         if (objectinputstream != null) {             objectinputstream.close();         }         if (bytesinputstream != null) {             bytesinputstream.close();         }     } catch (ioexception ex) {     } } 

to write data blob column use this:

preparedstatement preparedstatement = connection.preparestatement("update configuration_definition set bytes_data=? name=?", resultset.type_forward_only, resultset.concur_updatable); preparedstatement.setobject(1, bytestransformer.getinstance().getbytes(cfgdef)); preparedstatement.setstring(2, cfgdef.getname()); preparedstatement.executeupdate(); 

to retrieve data:

public configurationdefinition getconfigurationdefinition(string configname) {     byte[] bytes = null;     string sql = "select bytes_data configuration_definition name = '" + configname + "'";         resultset rs = getsqlconnector().executequerywithoutnoise(sql);     try {         if (rs == null || !rs.next()) {             return null;         }         blob blob = rs.getblob(blobcolumnname);         bytes = blob.getbytes(1, (int) blob.length());     } catch (sqlexception ex) {         gatewaylogger.error("unable extract db records configuration: " + configname, ex);         return null;     } {         getsqlconnector().closeresultset(rs);     }     configurationdefinition adefinition = (configurationdefinition) bytestransformer.getinstance().frombytes(buffer);             return adefinition; } 

most of time there no problem, (quite rarely) , seemingly no discernable pattern either:

java.io.streamcorruptedexception: invalid type code: <first_byte> 

or

java.io.streamcorruptedexception: invalid stream header: <first_four_bytes> 

when second error can find correct header starting few hundred bytes vector.

i should mention oracle schema holds aq jms queues use send serialized objects through , on couple of occasions objects of types retrieved oracle table though there no way 2 mixed in code.

i've looked around @ discussions exceptions , nothing seems apply case. looks in order far can tell , exceptions pop rarely.

any ideas?