code: private void moveInitializer(Field field, Method method, int position) {
      method.getFirstBlock().getAst().add(position,
          new ExpressionStatement(
              new FieldInitializationExpression(field.getAst())));
      field.getAst().setInitialValueExpression(null);
    }
docs: /*
  Moves initialization of the given field to the given position of the first block of the given method.