How to generate a dynamic "in (...)" sql list through Spring JdbcTemplate?

Yes, it's possible in Spring if you use NamedParameterJdbcTemplate or SimpleJdbcTemplate with named parameters. List parameter can be set as a java.util.List:

List<String> list = new ArrayList<String>();

list.add("A");
list.add("B");
list.add("C");

List<SomeObject> result = simpleJdbcTemplate.query("SELECT * FROM t WHERE c in (:list)",
    new RowMapper<SomeObject>() { ... },
    Collections.singletonMap("list", list));

In this case Spring internally creates the SQL query with the required number of placeholders based on the size of the actual list when replacing named parameters with ?s.