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Yong Liang
Yong Liang

Posted on • Updated on

Coming from Javascript, Arrays in Java are confusing?

Coming from Javascript, arrays in Java were confusing to me. Below I would like to discuss how arrays work in Java.

Array Declaration

In Java, an array has to declare with a type. Elements in it has to match the array type as well.

//integer array example, both declarations will work

int [] myArray; 
int myArray [];

//string array example

String [] strArray;
String strArray [];

Give array a size

The size of an array will not change dynamically in Java, so we have to define a size before using it. ArrayList is a better option when we need a dynamic size for a collection of datas.

//using the arrays from the examples above, we can define a size for them

myArray = new int[10];

//we can also perform the declaration and size with one line of code

int [] myArray = new int[10];

Array literal

When we know what elements that an array will have, we can use array literal to declare an array.

//the size of the array is determined by the number of elements were defined

int myArray = new int[]{1,2,3,4,5,6,7,8};

//in newer version of Java, we can skip the new int[]

int myArray = {1,2,3,4,5,6,7,8};

My favorite loop to use to get the array elements

for(int eachNumber : myArray){


Top comments (2)

hugueschabot profile image
Hugues Chabot

Java arrays are confusing even for Java programmers 😃. It's the only type that is covariant and reified. Like you wrote, prefer lists to arrays.

nerdlyist profile image
Coury Ryan Richards

I think over the last 7 years in Java I've used an array like this once and it was an interview question. List and Maps are way more useful. Java 8 gave us the stream api which is even more confusing but pretty dang slick.