Given an element , how to erase all the nodes with the given element value?

Ok, I have my Node class with some fields defined as an integer for the value (val) and a Node one for a reference. Also I have a second class called listaArmada with a Node head field that indicates the beginning of the list. I created a method class called borrarEle that receives a created list with some random values and an integer. The method must search within the list for nodes with the value of the given element and eliminate all nodes that contain it. It works but only removes the first element found and not the others as well. Should be able to remove any node that has that element regardless of position.

> List: 9,1,2,12,14,2,7,7,1,10
>
> value to eliminate: 7
>
> Expected output: 9,1,2,12,14,2,1,10
>
> Real output: 9,1,2,12,14,2,7,1,10

-------NODE CLASS

public class Nodo {
int val;
Nodo siguiente;

public Nodo(int ob, Nodo nxt){
    this.val = ob;
    this.siguiente = nxt;
  }
}

-------------------------------SECOND CLASS

public class listaArmada {

static public Nodo head;
static public int size;

static void borrarEle(int n, listaArmada ls){

    Nodo anterior = null;
    if(ls.head.val == n){//EL ELEMENTO ESTÁ EN LA CABEZA
        ls.head = ls.head.siguiente;
    }else{
        Nodo temp = ls.head;
        while(temp.siguiente.val != n){
            temp = temp.siguiente;

        }
        Nodo sg = temp.siguiente.siguiente;
        temp.siguiente = sg;
    }
}

The code in your question is not a minimal, reproducible example (MRE) so in the below code I added to your code in order to create a MRE. Basically, class ListaArmada is a singly linked list where each node in the list is an instance of class Nodo.

First I added method append() to class ListaArmada so as to be able to create a list. Second, I overrode method toString() in both ListaArmada and Nodo classes so as to facilitate testing and debugging.

I used the sample data you provided in your question. Also, I used OOP principles and java naming conventions.

public class ListaArmada {
    public Nodo head;

    public void append(int val) {
        Nodo n = new Nodo(val, null);
        if (head == null) {
            head = n;
        }
        else {
            Nodo next = head.getSiguiente();
            Nodo prev = head;
            while (next != null) {
                prev = next;
                next = next.getSiguiente();
            }
            prev.setSiguiente(n);
        }
    }

    public void borrarEle(int n) {
        if (head != null) {
            Nodo curr = head;
            Nodo prev = head;
            while (curr != null) {
                if (curr.getVal() == n) {
                    prev.setSiguiente(curr.getSiguiente());
                    if (curr == head) {
                        head = curr.getSiguiente();
                    }
                }
                else {
                    prev = curr;
                }
                curr = curr.getSiguiente();
            }
        }
    }

    public String toString() {
        StringBuilder sb = new StringBuilder();
        Nodo curr = head;
        while (curr != null) {
            sb.append(curr);
            curr = curr.getSiguiente();
        }
        sb.append("END");
        return sb.toString();
    }

    public static void main(String[] args) {
        ListaArmada la = new ListaArmada();
        la.append(9);
        la.append(1);
        la.append(2);
        la.append(12);
        la.append(14);
        la.append(2);
        la.append(7);
        la.append(7);
        la.append(1);
        la.append(10);
        System.out.println(la);
        la.borrarEle(7);
        System.out.println(la);
    }
}

class Nodo {
    private int val;
    private Nodo siguiente;

    public Nodo(int ob, Nodo nxt) {
        this.val = ob;
        this.siguiente = nxt;
    }

    public int getVal() {
        return val;
    }

    public Nodo getSiguiente() {
        return siguiente;
    }

    public void setSiguiente(Nodo n) {
        siguiente = n;
    }

    @Override
    public String toString() {
        return String.format("%d -> ", val);
    }
}

The append() method simply appends a new node to the end of the list.

The while loop in your borrarEle() method is wrong. You want to iterate through all the nodes in the list. You know that you have reached the last node in the list when its siguiente is null. You also need to handle the situation where you delete the first node in the list. In that case you also have to update head in class ListaArmada.

Running the above code produces the following output.

9 -> 1 -> 2 -> 12 -> 14 -> 2 -> 7 -> 7 -> 1 -> 10 -> END
9 -> 1 -> 2 -> 12 -> 14 -> 2 -> 1 -> 10 -> END