title: Null Exception array
body: <p>Hi I am working in string array and It seeming wont add the data in the array keep me getting an error or null exception</p>
  
  <pre><code>public boolean addCategory(String description){
  if(numCategories &lt;= maxArrayCategories){
      arrayCategories[numCategories] = description;
      numCategories++;
      return true;}
  else {return false;}}
  </code></pre>
  
  <p>Is the problem the function?</p>