Execution time insert sort

public class Main {

    public static void bubble(int[] array) {
        for (int i = 1; i <= array.length - 1; i++) {
            for (int j=0; j < array.length-1; j++) {
                if (array[j] > array[j + 1]) {
                    int aux = array[j];
                    array[j] = array[j + 1];
                    array[j + 1] = aux;
                }
            }
        }
    }

    public static void selection(int[] array) {
        for (int i=0; i < array.length-1; i++) {
            int lowestIndex = i;
            for(int j=i+1; j < array.length; j++) {
                if(array[j] < array[lowestIndex])
                    lowestIndex = j;
            }
            int aux = array[i];
            array[i] = array[lowestIndex];
            array[lowestIndex] = aux;
        }
    }

    public static void insercao(int vet[]) {
        for(int i = 1; i < vet.length; i++){
            int aux = vet[i];
            int j = i - 1;
            while (j >= 0 && vet[j] < aux) {
               vet[j + 1] = vet[j];
               j--;
            }
            vet[j + 1] = aux;
         }
    }

    public static void main(String[] args) {
        String response1 = "\nMetodo da bolha\n";
        String response2 = "\nMetodo da Seleção\n";
        String response3 = "\nMetodo da Inserção\n";

        for (int tam = 5000; tam <= 40000; tam = tam + 5000) {
            int[] array1 = new int[tam];
            int[] array2 = new int[tam];
            int[] array3 = new int[tam];

            for (int i = 0; i < tam; i++)
                array1[i] = array2[i] = array3[i] = (int) (Math.random() * 1000);

            long initialTime = System.currentTimeMillis();
            bubble(array1);
            long finalTime = System.currentTimeMillis();
            response1 += "Tamanho = " + tam + "  => Tempo = " + (finalTime - initialTime) + " ms\n";

            initialTime = System.currentTimeMillis();
            selection(array2);
            finalTime = System.currentTimeMillis();
            response2 += "Tamanho = " + tam + "  => Tempo = " + (finalTime - initialTime) + " ms\n";

            initialTime = System.currentTimeMillis();
            insercao(array3);
            finalTime = System.currentTimeMillis();
            response3 += "Tamanho = " + tam + "  => Tempo = " + (finalTime - initialTime) + " ms\n";
        }

        System.out.println(response1);
        System.out.println(response2);
        System.out.println(response3);
    }

}