How to fix the error: HTTP Status 500 - Servlet execution threw an exception?

Language: Java Server: Apache Tomcat. Environment: Eclipse.

I'm following Caelum's Handbook for course FJ21 - Web Development with Java. I created a form but at the time of writing it presents the following error:

  

HTTP Status 500 - Servlet execution threw an exception

     

type Exception report

     

message Servlet execution threw an exception

     

description The server encountered an internal error that prevented it from fulfilling this request.

     

exception

     

javax.servlet.ServletException: Servlet execution threw an exception       org.apache.tomcat.websocket.server.WsFilter.doFilter (WsFilter.java:53)   root cause

     

java.lang.Error: Unresolved compilation problem:     Unhandled exception type SQLException

     

br.com.caelum.jdbc.dao.ContatoDAO (ContactDAO.java:19)

     

    

br.com.caelum.agenda.servlet.AddingContactServlet.service (AddContactServlet.java:46)       javax.servlet.http.HttpServlet.service (HttpServlet.java:729)       org.apache.tomcat.websocket.server.WsFilter.doFilter (WsFilter.java:53)     note The full stack trace of the root cause is available in the Apache Tomcat / 9.0.0.M15 logs.

  

Follow the code of the ContactData class:

public class ContatoDAO {
  private Connection connection;

  public ContatoDAO()  {
    try {
      this.connection = new ConnectionFactory().getConnection();
    } catch (SQLException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }

  public void adiciona(Contato contato)  {
      String sql = "insert into contatos (nome, email, endereco, dataNascimento) values (?,?,?,?)";

      try {
        PreparedStatement stmt = connection.prepareStatement(sql);

        stmt.setString(1, contato.getNome());
        stmt.setString(2, contato.getEmail());
        stmt.setString(3, contato.getEndereco());
        stmt.setDate(4, new Date(contato.getDataNascimento().getTimeInMillis()));

        stmt.execute();
        stmt.close();
      } catch (SQLException e)  {
        throw new RuntimeException(e);
      }
  }
}

Contact Class:

public class Contato {
  private Long id;
  private String nome;
  private String email;
  private String endereco;
  private Calendar dataNascimento;
  public Long getId() {
    return id;
  }
  public void setId(Long id) {
    this.id = id;
  }
  public String getNome() {
    return nome;
  }
  public void setNome(String nome) {
    this.nome = nome;
  }
  public String getEmail() {
    return email;
  }
  public void setEmail(String email) {
    this.email = email;
  }
  public String getEndereco() {
    return endereco;
  }
  public void setEndereco(String endereco) {
    this.endereco = endereco;
  }
  public Calendar getDataNascimento() {
    return dataNascimento;
  }
  public void setDataNascimento(Calendar dataNascimento) {
    this.dataNascimento = dataNascimento;
  }
}