public DbSchemaChanger beginChange() throws Exception {
  backupFile=File.createTempFile("dataobj",".class");
  log.info("copy from {} to {}",classFile.getAbsolutePath(),backupFile.getAbsolutePath());
  copyFile(classFile,backupFile);
  cc.defrost();
  return this;
}

public DbSchemaChanger beginChange ( ) throws Exception { backupFile = File . createTempFile ( "dataobj" , ".class" ) ; log . info ( "copy from {} to {}" , classFile . getAbsolutePath ( ) , backupFile . getAbsolutePath ( ) ) ; copyFile ( classFile , backupFile ) ; cc . defrost ( ) ; return this ; }
begin change the schema this method should be called before making any changes to the class
