add in the JAVA Text file

In my code I wanted to add to the file but I can not, it always deletes the content from before.

package classejava;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.util.StringTokenizer;
import java.util.logging.Level;
import java.util.logging.Logger;
import jdk.internal.jfr.events.FileWriteEvent;

public class escritor {

    public static void entraVetor(float[] vetor, int n) {
        Scanner entrada = new Scanner(System.in);
        for (int i = 0; i < n; i++) {
            vetor[i] = entrada.nextFloat();

        }
    }

    public static void gravaArquivo(float[] vet, int n) throws IOException {

        FileWriter gravador = new FileWriter("arquivo.txt");
        BufferedWriter buffer = new BufferedWriter(gravador);
        for (int i = 0; i < n; i++) {
            buffer.write(" " + vet[i]);
            buffer.flush();
        }

    }

    public static void main(String[] args) throws IOException {
        Scanner entrada;
        entrada = new Scanner(System.in);
        float[] vet;
        int n;
        n = entrada.nextInt();
        vet = new float[n];
        entraVetor(vet, n);
        gravaArquivo(vet, n);

    }

}