Comparable with Arrays.Sort

Question

I’m having difficulties using the interface Comparable. In class TrabalhoGA I must call the method ordenaPorPontos class temporada2013 comparing the points of Pilotos of this class, I need to use the Arrays.sort to organize the pilot array. When running the Arrays.sort I get the following error:

Exception in thread "main" java.lang.Nullpointerexception at work.porPontos.compare(porPontos.java:21) at java.util.Timsort.binarySort(Timsort.java:265) at java.util.Timsort.Sort(Timsort.java:190) at java.util.Timsort.Sort(Timsort.java:173) at java.util.Arrays.Sort(Arrays.java:659) at work.temporada2013.ordenaPorPontos(temporada2013.java:49) Main(Work.java:56) Java Result: 1

Classe Trabalho:

    Piloto[] pontuaram = new Piloto[30];

public void inserePilotosPontuados(String driver, String team, int points) {
    for(int i=0;i<getLast();i++){
        if(pontuaram[i].getDriver().equalsIgnoreCase(driver)){
            pontuaram[i].setPts(pontuaram[i].getPts()+points);
            return;
        }

    }
    pontuaram[getLast()] = new Piloto(driver, team, points);
}

private int getLast() {
int last = 0;

for (int i = 0; i < pontuaram.length; i++) {
    if (pontuaram[i] == null) {
        last = i;
        return last;
    }
}

return last;
}

public void ordenaPorNome(){  
    Arrays.sort(pontuaram,new porNome());  
}  

public void ordenaPorPontos(){  
    Arrays.sort(pontuaram,new porPontos());  
}  

public void gravar(File arquivo)throws IOException{  
    PrintWriter gravar = new PrintWriter(new FileWriter(arquivo));  

    for (int i=0;i<pontuaram.length;i++){ 
        gravar.print(pontuaram[i]);  
    }
    gravar.close();  
}

public void mostraNaTela(){  
    int i = 0;
    while(pontuaram[i] != null && i<pontuaram.length){
        int numero = i+1;
        System.out.println("Classificado em "+numero+"° lugar:");
        System.out.println("Nome: "+pontuaram[i].getDriver());
        System.out.println("Equipe: "+pontuaram[i].getTeam());
        System.out.println("Pontos: "+pontuaram[i].getPts());
        System.out.println("----------------------------");
        i++;
    }
}

Sort Class:

    public int compare(Object obj1, Object obj2){  
    Piloto p1 = (Piloto) obj1;  
    Piloto p2 = (Piloto) obj2;  

    if (p1.getPts() == p2.getPts())  
        return 0;  
    else if (p1.getPts() > p2.getPts())  
        return -1;  
    else  
        return 1;  

P1 = work. Pilot@6f54c08a, P2 = work.Pilot@252cdd20 P1 = work. Pilot@246972f1, P2 = work.Pilot@6f54c08a P1 = work. Pilot@6f93ee4, P2 = work.Pilot@246972f1 P1 = work. Pilot@6f93ee4, P2 = work.Pilot@6f54c08a P1 = work. Pilot@6f93ee4, P2 = work.Pilot@252cdd20 P1 = work. Pilot@558fee4f, P2 = work.Pilot@6f54c08a P1 = work. Pilot@558fee4f, P2 = work.Pilot@252cdd20 P1 = work. Pilot@558fee4f, P2 = work.Pilot@6f93ee4 P1 = work. Pilot@5c66b06b, P2 = work.Pilot@252cdd20 P1 = work. Pilot@5c66b06b, P2 = work.Pilot@558fee4f P1 = work. Pilot@5c66b06b, P2 = work.Pilot@6f93ee4 P1 = work. Pilot@59c87031, P2 = work.Pilot@252cdd20 P1 = work. Pilot@59c87031, P2 = work.Pilot@246972f1 P1 = work. Pilot@59c87031, P2 = work.Pilot@6f54c08a P1 = work. Pilot@763dcf03, P2 = work.Pilot@252cdd20 P1 = work. Pilot@763dcf03, P2 = work.Pilot@5c66b06b P1 = work. Pilot@763dcf03, P2 = work.Pilot@558fee4f P1 = work. Pilot@53e20a9a, P2 = work.Pilot@252cdd20 P1 = work. Pilot@53e20a9a, P2 = work.Pilot@763dcf03 P1 = work. Pilot@53e20a9a, P2 = work.Pilot@5c66b06b P1 = work. Pilot@1d262f7c, P2 = work.Pilot@558fee4f P1 = work. Pilot@1d262f7c, P2 = work.Pilot@53e20a9a P1 = work. Pilot@1d262f7c, P2 = work.Pilot@763dcf03 P1 = work. Pilot@35f784d7, P2 = work.Pilot@558fee4f Exception in thread "main" java.lang.Nullpointerexception P1 = work. Pilot@35f784d7, P2 = work.Pilot@59c87031 P1 = work. Pilot@35f784d7, P2 = work.Pilot@6f54c08a P1 = work. Pilot@35f784d7, P2 = work.Pilot@252cdd20 P1 = work. Piloto@d 325aef, P2 = work.Pilot@558fee4f P1 = work. Piloto@d 325aef, P2 = work.Pilot@6f54c08a P1 = work. Piloto@d 325aef, P2 = work.Pilot@35f784d7 P1 = work. Pilot@64f007ad, P2 = work.Pilot@252cdd20 P1 = work. Pilot@64f007ad, P2 = work.Pilot@763dcf03 P1 = work. Pilot@64f007ad, P2 = work.Pilot@558fee4f P1 = work. Pilot@64f007ad, P2 = work.Pilot@1d262f7c P1 = work. Pilot@4a8822a0, P2 = work.Pilot@558fee4f P1 = work. Pilot@4a8822a0, P2 = work.Pilot@6f54c08a P1 = work. Pilot@4a8822a0, P2 = work.Pilot@246972f1 at work.porPontos.compare(porPontos.java:22) P1 = work. Pilot@2f995c9a, P2 = work.Pilot@252cdd20 P1 = work. Pilot@2f995c9a, P2 = work.Pilot@59c87031 at java.util.Timsort.binarySort(Timsort.java:265) P1 = work. Pilot@2f995c9a, P2 = work.Pilot@4a8822a0 P1 = work. Pilot@7d8e9adf, P2 = work.Pilot@252cdd20 P1 = work. Pilot@7d8e9adf, P2 = work.Pilot@59c87031 P1 = work. Pilot@7d8e9adf, P2 = work.Pilot@4a8822a0 P1 = work. Pilot@7d8e9adf, P2 = work.Pilot@2f995c9a P1 = work. Pilot@1d59e6df, P2 = work.Pilot@35f784d7 P1 = work. Pilot@1d59e6df, P2 = work.Pilot@246972f1 at java.util.Timsort.Sort(Timsort.java:190) P1 = work. Pilot@1d59e6df, P2 = work.Pilot@2f995c9a P1 = work. Pilot@1d59e6df, P2 = work.Pilot@7d8e9adf P1 = work. Pilot@79444986, P2 = work.Pilot@35f784d7 P1 = work. Pilot@79444986, P2 = work.Pilot@4a8822a0 P1 = work. Pilot@79444986, P2 = work.Pilot@7d8e9adf at java.util.Timsort.Sort(Timsort.java:173) P1 = work. Pilot@79444986, P2 = work.Pilot@2f995c9a P1 = null, P2 = work. Piloto@d 325aef at java.util.Arrays.Sort(Arrays.java:659) at work.temporada2013.ordenaPorPontos(temporada2013.java:49) Main(Work.java:56) Java Result: 1

Answer 1

porPontos.java:21

A variable referenced in the class porPontos.java on line 21 is null. Just check or change the logic to make sure it doesn’t get here with null value.