Initializer block contains the code that is always executed whenever an instance is created. It is used to declare/initialize the common part of various constructors of a class. For example,
Common part of constructors invoked!! Default Constructor invoked Common part of constructors invoked!! Parametrized constructor invoked
We can note that the contents of initializer block are executed whenever any constructor is invoked (before the constructor’s contents)
The order of initialization constructors and initializer block doesn’t matter, initializer block is always executed before constructor. See this for example.
Refer below article for more details in instance initialization:
Instance Initialization Block (IIB) in Java
What if we want to execute some code once for all objects of a class?
We use Static Block in Java
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above