Loading Jtable and processor gets high in process

Question

I’m making a sisteminha and in it has a JTable and I need to loader my data, I’ve been analyzing by task manager that when this table load function is called, it greatly increases the processor load. What can it be? I’ve tried it and I’m sure it’s because of that function. I remember that I’m NOT using the DefaultTableModel but one of mine. Does anyone know why? My processor is an i5 6500.

Class that contains the method of loading the table, remembering that I am using MVC, so it returns a ArrayList that will be used in mine TableModel.

package lifetech.model;

import java.sql.Connection;
import java.sql.Time;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import lifetech.util.Conexao;

public class TarefasDataDAO {

    private Conexao conexao = new Conexao();
    private Connection conn = conexao.conectar();

    public ArrayList carregarTabela(String date) throws ParseException{

        ArrayList linhas = new ArrayList();

            //Formata a data que é passada por parametro, para conseguir pesquisar no banco de dados
            SimpleDateFormat format = new SimpleDateFormat("dd/MM/yyyy");
            java.sql.Date data = new java.sql.Date(format.parse(date).getTime());



        try{

            String sql = "SELECT * FROM tb_tarefas WHERE data = ? ORDER BY id ASC";
            conexao.pstm = conn.prepareStatement(sql);
            conexao.pstm.setDate(1, data);
            conexao.rs = conexao.pstm.executeQuery();



            while(conexao.rs.next()){

                linhas.add(new Object[]{conexao.rs.getInt("id"),format.format(conexao.rs.getDate("data")),
                           conexao.rs.getString("titulo"), conexao.rs.getString("descricao"),
                           conexao.rs.getString("comeco"), conexao.rs.getString("termino"),
                           conexao.rs.getString("observacao"), conexao.rs.getString("status")});
            }

            return linhas;

        }catch(Exception ex){
            System.out.println("Erro ao preencher tabela de Tarefas da data " + date + "\n"
                                + ex.getMessage());
            return null;
        }finally{
            conexao.desconectar();
        }

    }

Tablemodel

package lifetech.model;

import java.util.ArrayList;
import javax.swing.table.AbstractTableModel;

public class TableModel extends AbstractTableModel {

    private ArrayList linhas;
    private String[] colunas;

    //Construtor

    public TableModel(ArrayList linhas, String[] colunas) {
        this.linhas = linhas;
        this.colunas = colunas;
    }

    //Metódos

    public String getColumnName(int numColumn){
        return this.colunas[numColumn];
    }

    @Override
    public int getRowCount() {
        return linhas.size();
    }

    @Override
    public int getColumnCount() {
        return colunas.length;
    }

    @Override
    public Object getValueAt(int numLinha, int numColuna) {
        Object[] linha = (Object[]) linhas.get(numLinha);
        return linha[numColuna];
    }

    //Getters e setters

    public ArrayList getLinhas() {
        return linhas;
    }

    public void setLinhas(ArrayList linhas) {
        this.linhas = linhas;
    }

    public String[] getColunas() {
        return colunas;
    }

    public void setColunas(String[] colunas) {
        this.colunas = colunas;
    }



}