title: Should we use collection, get and sets?
body: <p>I was reading a java book, where it said that when accessing/modifying  to variables in different class it should be use the get/set methods to manipulate them.</p>
  
  <p>My question is, overtime and in big projects using gets/sets will not jeopardize the application performance?</p>
  
  <p>Similar question, typically should we preferable use arrays in detriment of more abstract data type (such likened list of instance), since array are normally more cache friendly.</p>