All Questions

Starting from:

Don't promise what you can't deliver

You might assume that a promise in Javascript is based on this principle by ensuring that there will always be a ( expected? ) result.

Taking this code as an example:

var promesa = new Promise(
    function(resolve, reject) {
        alert('Hola mundo!');
    }
);

promesa.then(
    function(value) {
        alert('Hola universo!');
}).then(
    function(value) {
        alert('Hola multiuniverso!');
});

A serial process is triggered until show alert('Hola multiuniverso!');, which could also be done with nested Ajax Requests , which leads me to assume that there are also other advantages over a simple Ajax call.

The main questions would be (I know there are several and it is not so well seen within SOes, but with the explanation of what a promise is, several of them are resolved):

• What is a promise?
• Promisea plugin , a standard or a design pattern?
• Is ajax a promise type?
• Can promises be synchronous and asynchronous calls?

I have my Java program and I get a NullPointerException and I have seen other questions but they are from people with other programs and it does not work for my program and I want to leave you here the 2,000 lines of my program so that you can solve the problem for me but people do not let.

Look, my program is like this

  Object a = null;
  // 500 líneas de código
  // Dentro de un bucle, dentro de un if, dentro de un for...
  a = algunaFuncionDeMilLineasQueNoTeVoyAMostrar(
     parámetrosDeLosQueNoTeDiréElValor)
  // Cerrando for, cerrando if, cerrando bucle.
  // Otras 500 líneas de código
  // Una de estas líneas lanza el NPE, pero no te diré cuál.
  a.toString();
  z.hazAlgunaCosa();
  x.haxY().hazM().cuantoFaltaParaLasVacaciones().andaMiraUnPatoQuePasaPorAhi();

It's wrong? Why isn't there a one-size-fits-all solution for NullPointerExceptions (NPEs) if they happen so often?

I've found quite a few questions on StackOverflow about programs or web forms that save information to a database (especially PHP and MySQL) that contain serious security issues mainly related to SQL injection .

I usually leave a comment and/or a link to an external reference, but a comment doesn't leave much room and it would be nice if there was an internal SOes reference on the subject so I decided to write this question/answer: What is SQL injection and how to avoid it?

I am creating a mini game where the user tries to guess a name. But when I want to compare two text strings to see if they are the same it doesn't seem to work.

final String miNombre = "Jordi";
Scanner input = new Scanner(System.in);
System.out.println("Adivina mi nombre: ");

while (true) {
    String intento = input.next();
    if(intento == miNombre) {
        System.out.println("Acertaste!");
        break;
    } else {
        System.out.println("Intentalo de nuevo!");
    }
}

EXIT:

Adivina mi nombre: 
manuel
Intentalo de nuevo!
jordi
Intentalo de nuevo!
Jordi
Intentalo de nuevo!

I did a commit and immediately after I noticed that I committed changes that I don't want to push to the remote .

Is there a way to undo the same by keeping those changes in my working copy to recommit them correctly?