为什么程序显示“ NullPonterException”？

Question

通过计算得分和进球差来计算 UEFA冠军联赛排名的程序，并完成了该程序，这似乎是正确的，但它没有接受输入。请有人告诉为什么会引发NullPointerException。我已经尝试了很多次，但是没有用。

它将字符串或行作为：HomeTeamName HomeTeamGoals vs AwayTeamGoals AwayTeamName 然后，如果团队名称已经存在，则它将存储在其对象中。 否则它将存储在一个新对象中。 一个组中只有4个团队，因此仅创建了4个团队对象。 一个组将有12个匹配项，即为什么循环条件为12。

    class Team{
int point , gdiff ;
String name = new String();
Team(){
    point = gdiff  = 0;
    name = "NA";
}}
class Group{
private Team[] team;

Group() {
    this.team = new Team[4];
}
public void getData(){
    System.out.println("Enter Group Data as :HomeTeamName HomeTeamGoals vs. AwayTeamGoals AwayTeamName");
    Scanner scan = new Scanner(System.in);
    String match;
    for(int i=0;i<12;i++){
        match = scan.nextLine();
        String[] words = match.split(" ");
        int flag01 =0,flag02 = 0;
        for (Team team1 : team) {
            //probleum statement starts here 
            //NullPointerException is arising
            if (team1.name.equals(words[0])) {
                team1.gdiff += calculateGDiff(Integer.parseInt(words[1].trim()),Integer.parseInt(words[4].trim()));
                team1.point += calculatePoints(Integer.parseInt(words[1].trim()),Integer.parseInt(words[4].trim()));
                flag01 = 1;
                System.out.println(".....");
                continue;
            }
            if (team1.name.equals(words[5])) {
                team1.gdiff += calculateGDiff(Integer.parseInt(words[4].trim()),Integer.parseInt(words[1].trim()));
                team1.point += calculatePoints(Integer.parseInt(words[4].trim()),Integer.parseInt(words[1].trim()));
                flag02 = 1;
                System.out.println(".....");
            }
        }
        for (Team team1 : team) {
            if (flag01 == 0) {
                if (team1.name.equals("NA")) {
                    team1.name = words[0];
                    team1.gdiff += calculateGDiff(Integer.parseInt(words[1].trim()),Integer.parseInt(words[4].trim()));
                    team1.point += calculatePoints(Integer.parseInt(words[1].trim()),Integer.parseInt(words[4].trim()));
                    flag01 = 1;
                    System.out.println(".....");
                }
            }
            if (flag02 == 0) {
                if (team1.name.equals("NA")) {
                    team1.name = words[5];
                    team1.gdiff += calculateGDiff(Integer.parseInt(words[4].trim()),Integer.parseInt(words[1].trim()));
                    team1.point += calculatePoints(Integer.parseInt(words[4].trim()),Integer.parseInt(words[1].trim()));
                    flag02 = 1;
                    System.out.println(".....");
                }
            }
        }
    }   
}
private int calculateGDiff(int goals, int goalsR){
    return goals-goalsR;
}
private int calculatePoints(int goals, int goalsR){
    if(goals>goalsR)
        return 3;
    else if(goals==goalsR)
        return 1;
    else
        return 0;
}
}    

我只是正确地存储了目标和名称并删除了NullPointerException。