ExceptionInInitializerError Vs ArrayIndexOutOfBoundsException

[Harikrishna Gorrepati]

Hi, Please advice how ExceptionInInitializerError differs from ArrayIndexOutOfBoundsException.
I have given my understanding as given below in the comments.

class P236_Local {
	static int[] x = new int[4];
	static {
		x[4] = 5;
		// The above statement gives the following error.
		/**
		 * java.lang.ExceptionInInitializerError Caused by:
		 * java.lang.ArrayIndexOutOfBoundsException: 4 at
		 * P237_Local.<clinit>(P237_Local.java:4) Exception in thread "main"
		 */
	}

	public static void main(String[] args) {
		System.out.println(x[6]);// I am sure this gives ArrayIndexOutOfBoundsException.
	}
}

[Prasad Kharkar]

you must be knowing that static fields run according to the top down order

here we are creating static array variable and then static initializer block

in the static array creation, the array is created first

now in the static init block you are referring to the array index 5

Always remember that the arrays in java are zero index based

so the declaration new int[4] will create array containing 4 values that will be indexed as 0,1,2,3.

Now, by writing x[4] you are actually referring to the FIFTH element of array which is not possible at all as we created array of just 4 elements

so this causes the ArrayIndexOutOfBoundsException

and you are trying to give the value 5 to a variable that does not exist and cannot exist at all due to wrong array index

That means you cannot initilize the x[4] with value 5 and hence you are getting the ExceptionInInitializerError

Hope this helps
have a nice time

[Abimaran Kugathasan]

ExceptionInInitializerError : Signals that an unexpected exception has occurred in a static initializer. An ExceptionInInitializerError is thrown to indicate that an exception occurred during evaluation of a static initializer or the initializer for a static variable.

So, it will be thrown if there is a exception thrown in a static initializer. Have a look on the below example,

public class TestStaticIniException	{
	static	{
		if(true)	{
			throw new RuntimeException();
		}
	}

	public static void main(String[] args)	{
	}
}