Initialization block comes into play even before the constructor call, so that's why it is called first. So now your parent is created and the program can continue creating child class which will undergo the same process. Explanations: Static block of parent is executed first because it is loaded first and static blocks are called when the class is loaded. Community Bot 1 1 1 silver badge. Petr Mensik Petr Mensik Instance intialization blocks come into play during the constructor, after super is executed.
First - run child class only comment the extend clause to see the simple flow. Static init blocks are executed at the time of class loading. In the class hierarchy the order for execution of static init blocks will start from top level class.
In a class the order for the execution of static block is from top to bottom. Above rule apply regardless of where the static block is present within the class. Instance init blocks will be executed after the call to the super ; in the constructor.
Always super ; is the very first statement in a default constructor. In your code when you create a Child object: The default constructor of the Child class get executed. It will call to the super ; constructor. Then the super class constructor is executed. The Parent class will execute its super ; call. After that the instance init blocks in the Parent class are executed. From top to bottom. Then the code within the constructor is executed if any. Then it will return to the Child class and execute the Child class instance init blocks.
Finally the code in the child constructor get executed If exists. Andre Hofmeister 2, 11 11 gold badges 43 43 silver badges 70 70 bronze badges. Sayanthan Mahendran Sayanthan Mahendran 1 1 silver badge 3 3 bronze badges. Your second bullet point is correct, and your third bullet point contradicts it, so it is therefore incorrect.
Instance Initialization Blocks: Runs every time when the instance of the class is created. CKR Loading the chld class requires loading its parents. At the time of class loading, if we want to perform any task we can define that task inside the static block, this task will be executed at the time of class loading. In a class, any number of a static block can be defined, and this static blocks will be executed from top to bottom.
Static block executes before the main method while executing program. Statements written inside the static block will execute first. However both are static. When we have multiple static blocks then each block executes in the sequence. First static block will execute first. In Java, the initializer Block is used to initialize instance data members. The initializer block is executed whenever an object is created. For ex, Class class has a static block where it registers the natives.
If you need to do manipulation in order to initialize your static variables, you can declare a static block which gets executed exactly once, when the class is first loaded. Example: Use two static blocks, one to initialize a Map having languages and another to create a file. Output:- After executing above program, a log. A static variable gets created at the time of class loading even before the execution of static block and static method.
Consider you have a static variable serverUrl and you want to fetch the server url from database or a file and assign that value to the static variable serverUrl inside a static block.
You have a static method which is using value of static variable serverUrl. If static method executed before static block then there will not be server url value assigned to the static variable serverUrl you will get default value and not the value from the static block. The runtime system guarantees that static initialization blocks are called in the order that they appear in the source code.
Note: We use Initializer Block in Java if we want to execute a fragment of code for every object which is seen widely in enterprising industries in development. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. Skip to content. Change Language. Related Articles. Table of Contents. Save Article.
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