Getting errors working with String Arrays

Processing Coding Questions
5

Okay, so I defined all the things, and it looks like this:

int sessionhs = 0;
String shs = nf(sessionhs);                                         
String[] hs;                                  
String[] lasths;     
String ahs1;                             
int ahs;

void setup() {
  size(1920, 1080);
 lasths =  loadStrings("hs.txt"); 
}

void draw() {
  ahs1 = (lasths[0]);
  int ahs = int(ahs1);
   if (sessionhs > ahs) {
     hs[0] = ahs1;
     saveStrings("hs.txt", hs);
   }
}

However, with the .txt file present, I get this error message:

ArrayIndexOutOfBoundsException: 0