In framework code its used usually once in each class that needs to pull state on initialization ... so things like connection/object pools use it all the time.
i was lost in a silly mistake in the last question -
the task asks to initialize the cat variable in the static block.
I was initializing like this => Object obj = new Object();
and it should be obj = new Object();
I know its stupid. hope it helps if any of you faced the same.
it's not stupid:)
Of course, usually we initializing Object obj = new Object();
So it would be in our task: Cat cat = new Cat();
But we're already have a variable Cat cat.
That's why we just assign a new Cat() to this variable.
cat = new Cat();
I hope you understand it:) Let me know if you'll need any help:)
I did the same mistake, but then it made me wonder in the case of typing Cat cat = new Cat() versus cat = new Cat() would that mean that in the first case we are creating a complety different/new cat variable? Or would we still be using the same cat variable as created in: public static Cat cat; ? I'm just trying to understand if it makes a difference just in the CodeGym verifyer or in the real world.
Can someone explain why we nee static blocks? I am failing to see the utility in this concept. this lack of understanding hinders my ability to solve the problems.
Hi Michael,
Static block is like a method but has the highest precedence than the Class's constructor.
The static block gets executed only once even if you create multiple objects of that class. And in majority cases, static blocks used to assign or initialize static variables.
Basically we can think of static block as unit of code which needs to initialised even before any objects of the class is created . Lets say i have a static variable in my class the value of that variable can be initialised like below . When we define as a static variable , it will created when the class is loaded , even though no instances of the class is created . (Ideally when the class is referred some where this value is initialized. so we can directly access them with ClassName. variable name). Static block allows error handling also). The below code will help in initialising the path to be used by all instances of the class
private static String filePath = "C:\logs";
or
private static String filePath;
static{
filePath = "C:\logs";
}
Hello Codegym Team,
Again thanks for making this beautiful course available to us.
just a quick feedback:
for task: 1517: it should be hinted that only RuntimeException could be used.
I just got to know that RuntimeException does not need try and catch block for this program.
Bit interesting.
regards,
Manish
It also works if you use an if statement with other types of exceptions:
if(true)
throw new ExceptionInInitializerError();
Basically, you have to trick the IDE to not just prevent the code from compiling due to an obvious error.
Basically what i have understood here is that anything that have static and is not in main, they will be initialized from top to the beginning. So you should put them in the order you want to be initialized, either variables or methods
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