code: @SuppressWarnings("rawtypes")
  	public void setContractClasses(Class[] contractClasses) throws InvalidContractException {
  		contracts.clear();
  		for (int i = 0; i < contractClasses.length; i++) {
  			contracts.add(new ContractHolder(contractClasses[i]));
  		}
  		onCreate();
  	}
docs: Used to switch from a {@link Contract} to an other dynamically.<br/>
  Note that this may change the database schema.
  May be used for testing purpose. <br/>
  @param contractClass The {@link Contract} to switch to.
  @throws InvalidContractException