6 ways to declare and initialize a two-dimensional (2D) String and Integer Array in Java - Example Tutorial

Declaring a two-dimensional array is very interesting in Java as the Java programming language provides many ways to declare a 2D array and each one of them has some special things to learn about. For example, It's possible to create a two-dimensional array in Java without specifying the second dimension, sounds crazy right? but it's possible because a two-dimensional array in Java is nothing but an array of array. You can even create a two-dimensional array where each subarray has a different length or different type, also known as a heterogeneous array in Java. This means it's possible to create a two-dimensional array with variable column length in Java.

Recursive Binary Search Algorithm in Java - Example Tutorial

The binary search algorithm is one of the most famous search algorithms in computer science. It allows you to search a value in logarithmic time i.e. O(logN), which makes it ideal to search a number on a huge list. For example, in order to search a number in a list of 1 million numbers will take around 210 comparisons compared to 1 million comparisons required by the linear search algorithm. The only thing is that the list must be sorted before you can use a binary search algorithm and it must support index-based search. That's why binary search is often implemented using an array because doing a binary search with a linked list will not be fast because it doesn't provide index-based access i.e. O(1) access. You have to traverse to that element to read its value in the linked list which is O(n), effectively reducing the performance of binary search to a sequential search algorithm.

3 Ways to Convert an Array to ArrayList in Java? Example

How to convert an Array to ArrayList in Java
Have you encountered any situation where you quickly wanted to convert your array to ArrayList or ArrayList to array in Java? I have faced many such situations that motivate me to write these quick Java tips about converting an array to ArrayList and ArrayList to array in Java. Both array and ArrayList are quite common and every Java developer is familiar with this. Former is used to store objects and primitive types while later can only hold objects. The array is part of standard Java fundamental data structure while ArrayList is part of the collection framework in Java.

Difference Between Linked List and Array in Java? Example

Array and linked lists are two fundamental data structures in the programming world. Almost all programs use Array in some form or other, which makes it increasingly important to learn array and linked list. The difference between the linked list and array data structure is also a popular data structure question, frequently asked in the various programming job interviews. This makes it even more important to learn and understand the difference between an array and a linked list. Well, there are a lot of differences between these two starting from how they store data, to how you retrieve data from them.

How to Convert Byte Array to InputStream and OutputStream in Java? Example

Are you stuck with your coding because you have a byte array and the next method in the chain needs an InputStream? don't worry Java has a solution for that, You can use ByteArrayInputStream to convert byte array to InputStream in Java. This class takes a byte array as the source and since it's a subclass of InputStream, you can easily pass this to any method, which accepts InputStream as a parameter. Though most of the API like JDBC and File API allows you to read directly from InputStream because this allows you to process an arbitrary content with limited heap space. You should take advantage of this and directly read from InputStream instead of getting byte array and then converting them back to InputStream.

How to Convert InputStream to Byte Array in Java - 2 Examples

Sometimes we need to convert InputStream to byte array in Java, or you can say reading InputStream as a byte array, In order to pass output to a method that accepts byte array rather than InputStream. One popular example of this, I have seen is an older version of Apache commons-codec, while converting byte array to the hex string. Though, a later version of the same library does provide an overloaded method, to accept InputStream. Java File API provides excellent support to read files like image, text as InputStream in Java program, but as I said, sometimes you need String or byte array, instead of InputStream .

How to Reverse Array in Place in Java? Solution With Explanation

Reversing an array sounds pretty easy, isn't it? It does sound like that, because all you need to do is create an array of the same size, iterate through the original array from end to start, and populate your new array. Boom!!, you have got an array that has elements in reverse order of the original array, but the problem is you have used an additional array here, which makes space complexity of your solution O(n). You cannot use this solution if the array is big e.g. an array of 10 million orders and you don't have enough heap space available.