java - 如何修复线程“main”java.lang.NullPointerException中的异常？

Question

我是Java编程的初学者。我知道有关此特定消息错误的主题数量，但我无法解决此问题。该错误在以下代码的第 23 行中指示。我知道这个问题似乎与空引用有关，但我没有看到我的方法“Recommander”如何没有为所有引用分配值。

公共类推荐人{

// predetermined array of series 
private String[]  serie= {"Friends S1","Friends S2",
     "Friends S6","Friends S7", "Friends S8", "How I met your mother S1",
    "How I met your mother S2","How I met your mother S3 ","Castle S3", 
    "Santa Clarita Diet S1", "Modern Family S1","Modern Family S2",
    "Family Guy S6", "The Simpsons S5"}; 

// array of the purchases of one customer  
private int[] profil ; 

//number of profiles in the database
private int nbProfils = 10 ; 

// array of all the profiles from the database and the series available
private int[][] records ;

// creation of an instance of the object Recommander 
public Recommander() { 
    for (int k=0;k<=nbProfils-1; k++) {
        for (int i=0; i<=serie.length-1;i++) { 
            records[k][i]= (int) (Math.random())*2 ; 
        }
    } 
} 

// Display of the series available in store
public String affichageSerie() { 
    String Affichage = "" ; 
    for (int i = 0 ; i<=serie.length-1; i++) { 
        Affichage = Affichage + serie[i] +  "\n" ; 
    } 
    return Affichage  ;
} 

}

Answer 1

初始化数组

 private int[][] records = new int[nbProfils][serie.length];