TheServerSide
theserverside.com › blog › Coffee-Talk-Java-News-Stories-and-Opinions › Java-array-size-explained-by-example
Java array size, length and loop examples
A common example of the Java array length property being used in code is a program looping through all of the elements in an array.
Codecademy
codecademy.com › docs › java › arrays › .length
Java | Arrays | .length | Codecademy
April 21, 2025 - Learn to code in Java — a robust programming language used to create software, web and mobile apps, and more. Beginner Friendly.Beginner Friendly17 hours17 hours ... The .length property returns an integer value that represents the number of elements in the array. This example uses the .length ...
arrays - length and length() in Java - Stack Overflow
In the first case (20-25) the code ... of the array (in JNI this would have been a call to GetArrayLength()) whereas in the String case (28-35) it needs to do a method call to get the length. In the mid 1990s, without good JITs and stuff, it would have killed performance totally to only have the java.util.Vector ... More on stackoverflow.com
How do I use split() to get user inputs for an array without altering the length of the array?
Please ensure that: Your code is properly formatted as code block - see the sidebar (About on mobile) for instructions You include any and all error messages in full You ask clear questions You demonstrate effort in solving your question/problem - plain posting your assignments is forbidden (and such posts will be removed) as is asking for or giving solutions. Trying to solve problems on your own is a very important skill. Also, see Learn to help yourself in the sidebar If any of the above points is not met, your post can and will be removed without further warning. Code is to be formatted as code block (old reddit: empty line before the code, each code line indented by 4 spaces, new reddit: https://i.imgur.com/EJ7tqek.png ) or linked via an external code hoster, like pastebin.com, github gist, github, bitbucket, gitlab, etc. Please, do not use triple backticks (```) as they will only render properly on new reddit, not on old reddit. Code blocks look like this: public class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!"); } } You do not need to repost unless your post has been removed by a moderator. Just use the edit function of reddit to make sure your post complies with the above. If your post has remained in violation of these rules for a prolonged period of time (at least an hour), a moderator may remove it at their discretion. In this case, they will comment with an explanation on why it has been removed, and you will be required to resubmit the entire post following the proper procedures. To potential helpers Please, do not help if any of the above points are not met, rather report the post. We are trying to improve the quality of posts here. In helping people who can't be bothered to comply with the above points, you are doing the community a disservice. I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns. More on reddit.com
13
5
March 18, 2023Why is getting the length of an array O(1) and not O(n)?
Most implementations store the length of an array in the object itself. Whenever you insert/remove it gets updated. Thus you're not iterating to get the length you're just getting a value. More on reddit.com
45
11
November 7, 2022What does arr.length - 1 mean?
Consider this array: const arr = [3, 6, 9, 12] Because arrays are zero-indexed, our left-most element is arr[0]. Our array length is arr.length which is 4. Our right-most element is the fourth element arr[3]. We can find the index of that element by subtracting 1 from array.length. Get it? More on reddit.com
7
7
October 30, 2022Can we get array length using reflection in Java?
Yes, you can use the Array.getLength() method from the java.lang.reflect package. It’s useful when dealing with arrays generically without knowing the type at compile time. It's commonly used in frameworks and utility libraries.
upgrad.com
upgrad.com › home › tutorials › software & tech › array length in java
Java Array Length with Examples & Syntax
Is .length a method or a property in Java arrays?
In Java, .length is a property of arrays, not a method. Unlike String.length() or ArrayList.size(), you don’t use parentheses. It directly returns the total number of elements the array can hold. In Java, .length is a property of arrays, not a method. Unlike String.length() or ArrayList.size(), you don’t use parentheses. It directly returns the total number of elements the array can hold.
upgrad.com
upgrad.com › home › tutorials › software & tech › array length in java
Java Array Length with Examples & Syntax
Can array length in Java be changed after initialization?
No, array length in Java is fixed once the array is created. If you need a resizable structure, consider using collections like ArrayList. To change size, you must create a new array and copy data manually or use Arrays.copyOf().
upgrad.com
upgrad.com › home › tutorials › software & tech › array length in java
Java Array Length with Examples & Syntax
Videos
03:37
Difference between length() and length() in Java - YouTube
00:51
How to find length of array in Java tutorial - YouTube
How to Find Array Length in Java
02:39
Find the size of an array in java - YouTube
03:14
Java Array Length vs. Size - Video | Study.com
01:02
How to find the length of an Array? | Java Array Handling: Finding ...
W3Schools
w3schools.com › java › ref_arrays_length.asp
Java Array length Property
Java Examples Java Videos Java Compiler Java Exercises Java Quiz Java Code Challenges Java Practice Problems Java Server Java Syllabus Java Study Plan Java Interview Q&A ... The length property returns the length of an array.
Upgrad
upgrad.com › home › tutorials › software & tech › array length in java
Java Array Length with Examples & Syntax
June 4, 2025 - Explanation: We are accessing the length of the array cities, which contains 3 elements. Enhance your abilities through these best-in-class courses/certifications. upGrad’s AI-Powered Full Stack Development Course by IIITB · upGrad’s Professional Certificate Program in Cloud Computing and DevOps ... Java offers a few ways to determine array size depending on what you're trying to do.
Software Testing Help
softwaretestinghelp.com › home › java tutorial for beginners: 100+ hands-on java video tutorials › java array length tutorial with code examples
Java Array Length Tutorial With Code Examples
April 1, 2025 - This program is to find the minimum element in the array. import java.util.*; class Main { public static void main(String[] args) { int[] intArray = { 72,42,21,10,53,64 }; //int array System.out.pr
Alvin Alexander
alvinalexander.com › java › java-array-length-example-length-method
A Java array length example | alvinalexander.com
August 4, 2024 - The approach you take just depends on whether you want to use a arrayLength variable in your code, or if you just want to access the array length attribute (toppings.length). Either of these two Java array length approaches will print the following output:
HappyCoders.eu
happycoders.eu › java › array-length-in-java
Array Length in Java
June 12, 2025 - The length of an array is defined when it is initialized. The following code, for example, creates a string array of size four: String[] fruits = {"jujube", "apple", "boysenberry", "cherry"};Code language: Java (java)
CodeAhoy
codeahoy.com › java › array-length
Array Length in Java with Examples | CodeAhoy
January 26, 2020 - public class ArrayLength { public static void main(String[] args) { // Let's define some arrays int[] arrNumbers = {1,2,3,4}; char[] arrCharacters = {'a', 'b', 'c'}; String[] arrStrings = {"java", "c++", "c", "react", "spring"}; Object[] arrObj = new Object[10]; // new array with uninitialized elements // Print length of arrays System.out.println("arrNumbers.length is: " + arrNumbers.length); System.out.println("arrCharacters.length is: " + arrCharacters.length); System.out.println("arrStrings.length is: " + arrStrings.length); System.out.println("arrObj.length is: " + arrObj.length); } }
Edureka
edureka.co › blog › array-length-in-java
Array Length In Java | Java Array Examples | Edureka
December 4, 2023 - It must be noted, that Java Array Object does not have a method to get its length. Often times, we are unaware of how the array object was created. For such programs, we use a function that receives an array, and prints the length. /** * An Example to find the Java Array Length using a function */ public class ArrayLengthJava { private static void printArrayLength(String[] myArray) { if (myArray == null) //to check whether the array is empty or not { System.out.println("The length of the array can't be determined."); } else { int arrayLength = myArray.length; System.out.println("The length of
Top answer 1 of 8
134
Let me first highlight three different ways for similar purpose.
length -- arrays (int[], double[], String[]) -- to know the length of the arrays
length() -- String related Object (String, StringBuilder, etc) -- to know the length of the String
size() -- Collection Object (ArrayList, Set, etc) -- to know the size of the Collection
Now forget about length() consider just length and size().
length is not a method, so it completely makes sense that it will not work on objects. It only works on arrays.
size() its name describes it better and as it is a method, it will be used in the case of those objects who work with collection (collection frameworks) as I said up there.
Now come to length():
String is not a primitive array (so we can't use .length) and also not a Collection (so we cant use .size()) that's why we also need a different one which is length() (keep the differences and serve the purpose).
As answer to Why?
I find it useful, easy to remember and use and friendly.
2 of 8
27
A bit simplified you can think of it as arrays being a special case and not ordinary classes (a bit like primitives, but not). String and all the collections are classes, hence the methods to get size, length or similar things.
I guess the reason at the time of the design was performance. If they created it today they had probably come up with something like array-backed collection classes instead.
If anyone is interested, here is a small snippet of code to illustrate the difference between the two in generated code, first the source:
public class LengthTest {
public static void main(String[] args) {
int[] array = {12,1,4};
String string = "Hoo";
System.out.println(array.length);
System.out.println(string.length());
}
}
Cutting a way the not so important part of the byte code, running javap -c on the class results in the following for the two last lines:
20: getstatic #3; //Field java/lang/System.out:Ljava/io/PrintStream;
23: aload_1
24: arraylength
25: invokevirtual #4; //Method java/io/PrintStream.println:(I)V
28: getstatic #3; //Field java/lang/System.out:Ljava/io/PrintStream;
31: aload_2
32: invokevirtual #5; //Method java/lang/String.length:()I
35: invokevirtual #4; //Method java/io/PrintStream.println:(I)V
In the first case (20-25) the code just asks the JVM for the size of the array (in JNI this would have been a call to GetArrayLength()) whereas in the String case (28-35) it needs to do a method call to get the length.
In the mid 1990s, without good JITs and stuff, it would have killed performance totally to only have the java.util.Vector (or something similar) and not a language construct which didn't really behave like a class but was fast. They could of course have masked the property as a method call and handled it in the compiler but I think it would have been even more confusing to have a method on something that isn't a real class.
TheServerSide
theserverside.com › blog › Coffee-Talk-Java-News-Stories-and-Opinions › How-do-I-find-the-Java-array-length
How do I find the Java array length?
Initialize the Java array to a non-null value. Use the length property of the array to get its size.
Javatpoint
javatpoint.com › how-to-find-array-length-in-java
How to Find Array Length in Java - Javatpoint
How to Find Array Length in Java - How to Find Array Length in Java with java tutorial, features, history, variables, object, class, programs, operators, for-loop, oops concept, array, string, map, math, methods, examples etc.
iO Flood
ioflood.com › blog › java-array-length
Java Array Length: How To Get the Array Size in Java
February 27, 2024 - In Java, you can use the .length property of an array to find its length by using the syntax, int length = array.length;. It’s a simple and straightforward way to determine the size of your array.
Great Learning
mygreatlearning.com › blog › it/software development › how to find array length in java
How to find Array Length in Java
September 12, 2024 - To understand better, go to the section 'Searching for the highest value in the array' of this article, where we discussed an example. A. There are different scenarios to find the length. For example, we have two options to use the length() method or the java length attribute.
GeeksforGeeks
geeksforgeeks.org › java › how-to-find-length-or-size-of-an-array-in-java
How to Find Length or Size of an Array in Java? - GeeksforGeeks
The length property is the most common way to find the size of an array in Java. It gives the exact number of elements present in the array. Example: This example demonstrates how to find the length (size) of an array using the length property.
Published July 12, 2025
Dot Net Perls
dotnetperls.com › array-length-java
Java - Array Length - Dot Net Perls
Accessing length is fast. And in loops, using length directly, not a local variable, may lead to better performance. Let us use an array's length in a simple context. We find that the array here has three elements.
EyeHunts
tutorial.eyehunts.com › home › java array length method and examples
Java Array Length | Method ? Examples - EyeHunts
May 17, 2021 - Java array length can’t change after initialization. Note: This example (Project) is developed in IntelliJ IDEA 2018.2.6 (Community Edition) JRE: 11.0.1 JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o macOS 10.14.1
Study.com
study.com › business courses › java programming tutorial & training
Array Lengths in Java | Study.com
In our example, 'ages.length' has the value of 5. Array elements can also be initialized with values at declaration time through the use of '=' followed by a comma separated list of values enclosed in curly brackets ('{...}'). For example: ... ...
Scaler
scaler.com › home › topics › how to find array length in java
How to Find Array Length in Java - Scaler Topics
April 4, 2024 - While Java lacks a dedicated method for this, accessing length with the array's name provides quick insight into its size. Arrays store uniform-type elements in a fixed-size structure. Syntax: The number of elements in the array at the time of declaration is referred to as the array's size or length. The length of an array named A is supplied by the following code: Let’s take few examples to understand how length attributes really work.
GeeksforGeeks
geeksforgeeks.org › how-to-determine-length-or-size-of-an-array-in-java
How to determine length or size of an Array in Java? - GeeksforGeeks
July 17, 2023 - Below is the implementation of the above approach: ... Integer Array: [1, 2, 3, 4, 5, 6, 7] String Array: [GFG, GEEKS, GEEKSFORGEEKS] Size of integer array = 7 Size of string array = 3 ... The length() method is a method of the java.lang.String ...