The arrays we used so far were uniform series arrays, where all the array elements stay in a simple list, like in a column. This is the structure of onedimensional array, where all elements fit in one list (life is very simple). But sometimes, you may need to divide the list in a delimited sections.
Java TwoDimensional Array
Java Array
We know that variables are used to store data in a Java program. We also know that each variable can store not more than one data item. So, what do we do if we need to store a large number of data items, say 50. Well, we can use 50 variables, one for each of the 50 data items, but we need to write 50 lines of code for setting up these variables, or we can use ARRAYs. Which will need just a single line. Most realworld programs handle vast amount of data. An array with loops can relatively handle a vast amount of data.
Array Elements 
Nth Fibonacci number using Java Recursion
There are certain problems that just make sense to solve using Java Recursion. Demonstrating Fibonacci Series is one of them. Let’s take a look at something called Fibonacci series. Here are the first few numbers of this series:
0, 1, 1, 2, 3, 5, 8, 13, 21…
Russian Peasant Multiplication
This method involves a process of halving and doubling, which reduces one factor to powers of two and uses the distributive property of multiplication over addition to calculate a product.
Java Recursion Method
This is one of my favorite part of java programming. It is little bit complex with its function. And obviously, it will turn to be a fun part, if you get it. It is called Java Recursion.
So what is Java Recursion?

_You need to figure out a stopping
point which can be resolve without calling recursive function.
_With calling every recursive method, you must reduce or approach to the stopping point otherwise you will get java.lang.StackOverFlowError(Learn more about StackOverFlowError)