What does 'dependency injection' solve in PHP? [duplicate]

Question

Possible Duplicate:
What is dependency injection?

What is the hipe around 'dependency injection' adapted from Java and introduced in Symfony 2? Could someone give an example of a problem and a solution with and without a dependency injection?

Answer 1

Explanation that fits to PHP: http://fabien.potencier.org/article/11/what-is-dependency-injection

BTW: It's not from Java world only. DI and variations of DIC are used in most of high level programming languages. It's an universal practice helping you to write more maintanable code.