There was a very simple code to implemented. It brings me a lot of fun when I started the research. I had an array of different objects and I wanted to join them into one string in a special way. An important question here was: How objects will look like after casting into a string? The answer was short - good ;) But this is not the clue of this article. The most important question is: Why objects are cast into string in this way? Here is what I discover during my research.