Where to close result set

Where to close result set

I am getting result set is already closed where i am passing resultset
into other method.where should i closed result set.
public void mainTest(){
ResultSet rs= pstmt.executeQuery(query);
List list = populateRS(rs);
if(rs!=null)rs.close();
}
public List populateRS(ResultSet rs){
//work with result set
if(rs!=null)rs.close();
}