title: Class for storing data in java, simulating a mysql table
body: <p>I want to use a class in Java for storing data which can be accessed for all other classes. Just like if it was a Mysql table. </p>
  
  <p>This class should have only one instance, this way whenever its content is changed, all classes see the same content.</p>
  
  <p>What is the best way to do it? I have read about the singleton pattern, but I don't know if it would be a design error to use it. </p>