null pointer exception cannot be removed

class list { public int integer; public String elem; public list next; private Exception nothing; public int r;

public list() {
    this(null,null,0);
}

public list(String e,int i) {
    this.elem = e;
    this.next = null;
            this.integer=i;
}

public list(String e, list n ,int i) {
    elem = e;
    next = n;
            integer=i;
}

public void addElem(String newElem,int i1 ) {
    if (this.elem == null) {
        this.elem = newElem;
        this.next = null;
                    this.integer=i1;
    } else {
        list l = new list(elem, next, integer);

        this.next = l;
        this.elem = newElem;
                    this.integer=i1;
    }
}

public String getFirst() {
    return elem;
}

    public boolean isEmpty() {
    if (next.getNext()==null)
                return true;
            return false;
}




public String getElem() {
    return elem;
}

    public int getint() {
    return integer;
}

public list getNext() {
    return next;
}
    public int length(list next) {
      int o =0;
     while(next.elem != null){
         o++;
         next = next.getNext();

     }
     return o;
    }


    public void setNext(list next)

{ this.next=next; }

}

class arraylist{ public static list[] abcd; public static int p=0; public int q=0; public static int i=0;

public arraylist() { int x=0; for(x=0;x<5001;x++){ this.abcd[x] = new list(); }}

public static int ascii(String s){ int f=0;

for (int i=0; i

} return f; }

  public static int ascii3(String s){
int g=0;

for (int k=0; k((int)s.charAt(k)-96)((int)s.charAt(k)-96);

} return g;
}

public static String finder(int p,int q){
 int y=0;

for (y=0;y

   }
 else 
     arraylist.abcd[p] =  arraylist.abcd[p].getNext();

}

return "not found"; }

}

class FileRead {

public static int ascii(String s){ int f=0;

for (int i=0; i

} return f; }

  public static int ascii3(String s){
int g=0;

for (int i=0; i((int)s.charAt(i)-96)((int)s.charAt(i)-96);

} return g;
}

public static String finder(int p,int q){

   int i;

while (arraylist.abcd[p].getint()!=0) { if(q==arraylist.abcd[p].getint()) { arraylist.abcd[p] = arraylist.abcd[p].getNext(); return arraylist.abcd[p].getElem();

   }
 else 
     arraylist.abcd[p] =  arraylist.abcd[p].getNext();

}