title: Is this the correct way to use an instance variable in Java?
body: <p>I have a class that reads a configuration file once and puts all the parameters (key/value pairs) in a <code>Map</code>. </p>
  
  <p>For retrieving values from the Map instance I have created a method that takes a key and return the corresponding value.
  The config map is passed to all the classes that need to read from the configuration.  Each class that uses it reads the configuration parameters it needs and stores them in instance variables which are referred to in the rest of the class.</p>
  
  <p>Is it correct to use an instance variable and store the value in that or should I call the accessor method on the config object whenever I am required to get the value for any key?</p>