create or alter procedure POST_SEL
returns (
    ID1 INTEG,
    NAIM1 STR_MIDDLE)
as
begin
  for
     select id, naim from post into :id1, :naim1 
  do
  suspend;
end 

        ResultSet rs=null;
        Statement Statmt=null;
        String query="SELECT ID, NAIM FROM POST";  
        DB qq=new DB();      // Класс для работы с конкретной БД: соединение с БД и т.д.
        qq.Set_Connection();// Соединяемся с БД
        try 
        {
            Statmt = qq.con.createStatement();
            rs = Statmt.executeQuery(query);
        } 
        catch (SQLException ex) { ex.printStackTrace();} 

        String query="{call post_sel()}";       
        DB qq =new DB();
        qq.Set_Connection();
        CallableStatement cstmt;
        ResultSet rs=null;
        cstmt = qq.con.prepareCall(query);
        try 
       {    
            cstmt.executeQuery();
            rs=cstmt.getResultSet();
        } 
        catch (SQLException ex) { ex.printStackTrace(); }

ArrayList<M_Post> list = new ArrayList<M_Post>();
boolean bNext=false;       
        try {
                bNext=rs.next();
                while(bNext)
                {
                    M_Post post = new M_Post();
                    post.setId(rs.getInt("id"));
                    post.setNaim(rs.getString("naim"));
                    list.add(post);
                    bNext=rs.next();
                }
            } catch (SQLException ex)   { ex.printStackTrace(); }   
        return  list;

CREATE OR REPLACE FUNCTION public.post_sel()
    RETURNS refcursor
    LANGUAGE 'plpgsql'
AS $function$
declare 
mycursor refcursor;
begin
open mycursor FOR SELECT * FROM public.post;
return mycursor;
end
$function$;

public class JavaWithPostgreSQL {
    private static final String ClassDrive="org.postgresql.Driver";
    private static final String URL_Connect="jdbc:postgresql://localhost:5432/postgres";
    private static  Statement Statmt=null;
    private static CallableStatement cstmt=null;
    private static  ResultSet rs = null;
    public static Connection con;
    
    public static void main(String[] args) 
    {              
    try {
            Class.forName(ClassDrive);
            try {
                con = DriverManager.getConnection(URL_Connect, "postgres", "1");
            } catch (SQLException ex) { Logger.getLogger(JavaWithPostgreSQL.class.getName()).log(Level.SEVERE, null, ex);}   
        } 
        catch (ClassNotFoundException ex){ ex.printStackTrace();}           
    
    String query="{  ?=call public.post_sel()}";
            try {
               con.setAutoCommit(false);
               cstmt = con.prepareCall(query);
               cstmt.registerOutParameter(1, Types.OTHER);
               cstmt.execute(); 
               rs=(ResultSet) cstmt.getObject(1);
            } catch (SQLException ex) {  Logger.getLogger(JavaWithPostgreSQL.class.getName()).log(Level.SEVERE, null, ex);  }       
    System.out.println("BEGIN");
    boolean bNext=false;       
        try {
                bNext=rs.next(); 
                while(bNext)
                {
                    System.out.print(rs.getInt("id"));
                    System.out.print("__");
                    System.out.println(rs.getString("naim"));
                    bNext=rs.next();
                }
            } catch (SQLException ex)   { ex.printStackTrace(); }  
    System.out.println("END");   
    }      
}