Trending November 2023 # How Does Alias Work In Java With Programming Examples # Suggested December 2023 # Top 13 Popular

You are reading the article How Does Alias Work In Java With Programming Examples updated in November 2023 on the website Cancandonuts.com. We hope that the information we have shared is helpful to you. If you find the content interesting and meaningful, please share it with your friends and continue to follow and support us for the latest updates. Suggested December 2023 How Does Alias Work In Java With Programming Examples

Introduction to Java alias

In Java, when multiple references are used to refer to the same object, it is commonly referred to as “alias.”The issue with aliasing is when a user writes to a particular object, and the owner, for several other references, does not expect that object to change. Here, the code that includes aliasing can get confusing fast, and it is very tedious to debug as well. Let us see how Java Alias works.

Start Your Free Software Development Course

Web development, programming languages, Software testing & others

How does an alias work in Java?

Let us take an example. x and y are two variable names that have two types, X and Y. Y extends X.

Y[] y = new Y[10]; X[] x = y; x[0] = new X(); Y[0].func1();

In memory as well, they both point to the same location.

The memory location which is pointed is pointed by x as well as y. However, the actual object saved chooses which method to call during runtime.

Let us see another example.

Rectangle b1 = new Rectangle (0, 0, 50, 150); Rectangle b2 = b1;

Both b1 and b2 refer to the same object, or we can say that the given object has two names, such as b1 and b2. Similar to a person that has two names, objects can also have two names.

When two aliased variables are present, changes that cause one variable also reflect on the other, as shown below.

System.out.println (b2.width); b1.grow (40, 40); System.out.println (b2.width);

On executing the code, you will see that the changes that have been caused on one rectangle have occurred in the second rectangle as well. This is one of the main things that has to be noted for Alias in Java.

Examples of Java Alias

The following are some of the sample programs on Java Alias.

Example #1

Code:

class X { public void func1() { System.out.println("called sample function 1"); } } class Y extends X { public void func1() { System.out.println("called sample function 1"); } public void func2() { System.out.println("called sample function 2"); } } public class AliasExample { public static void main(String[] args) { Y[] y = new Y[10]; X[] x = y; x[0] = new X(); y[0].func1(); } }

Output:

How this occurs? What has to be changed? Is it possible to solve this?

Yes!! The only reason for this exception is that Java manages aliases during runtime. Only during the run time will it be able to know that the first one should be an object of Y instead of X.

Output:

Example #2

Code:

public class AliasExample { public static void main(String[] args) { int a= 87; int b=87; System.out.println(a == b); b=a; System.out.println(a == b); } }

What will happen if two arrays, a and b, are used instead of integer variables?

public class AliasExample { public static void main(String[] args) { int []a = {81, 54, 83}; int []b = {81, 54, 83}; System.out.println(a == b); b=a; System.out.println(a == b); } }

Output:

In this program, two arrays, a and b, are created in the first step. Then, similar to the above program, a and b check whether they are equal. On executing the code, it can be seen that the output for the first check is false, and the output for the second check is true. It is because Java Alias works.

Conclusion

The drawback of alias is when a user writes to a specific object, and the owner, for some other references, does not guess that object to change.

Recommended Articles

This is a guide to Java Alias. Here we discuss how alias works in java along with programming examples for understanding better. You may also have a look at the following articles to learn more –

You're reading How Does Alias Work In Java With Programming Examples

How Reduce Function Work In Scala With Examples

Introduction to Scala reduce Function

Scala reduces functions to reduce the collection data structure in Scala. This function can be applied for both mutable and immutable collection data structures. Mutable objects are those whose values change frequently, whereas immutable objects are those objects that one assign cannot change itself. Reduce function can be applied to map, sequence, set, list, etc. This function returns a single value from the collection data structure. In reducing function, it merges all the values from the collection data structure and returns on a single value.

Start Your Free Software Development Course

Web development, programming languages, Software testing & others

Syntax

Below is the syntax of Scala reduce:

Explanation: In the above syntax, we have prepared one collection followed by the reduced function. It takes two parameters on which we can perform our operation. At last, we will obtain one value as output.

How does reduce Function work in Scala?

Reduce function reduces the number of elements in the collection data structure. What it does internally is it uses binary operation and merges all the available elements into one single element. We can see how it works internally. Suppose we have one list of elements like 3, 7, 9, 2, 1, 5. Now we will apply to reduce function to generate a single number after adding all the numbers from the list.

1. First, it will take the first element 3. Then it will apply a binary operation on the first and second numbers and merge them to generate the third number.

Now we can have a look at one practical example for beginners for more understanding:

Code:

object Main extends App{ val collection = List(200 , 400, 100, 30, 1000, 500) }

Explanation: In this example, we create one collection data structure list. After that, we apply to reduce function on the list to try to find out the max element from the list of elements. This will also return as a single value from the list of elements.

Extended class:

AbstractIterable[(K, V)]

Map[K, V]

Some of the supertype:

Map

Equals

MapFactoryDefaults

MapOps

PartialFunction

AbstractIterable

Iterable

IterableFactoryDefault

IterableOps

IterableOnceOps

Some known classes:

TrieMap

AbstractMap

HashMap

IntMap

ListMap

Longman

Map1

Map2

Map3

Map4

withDefault

TreeMap

TrrSeqMap

VectorMap

AbstractMap

AnyRefMap

CollisionProofHashMap

LinkedHashMap

LongMap

WithDefault

SystemProperties

ListMap

OpenHashMap

reduceLeft

reduceRight

reception

reduceRightOPtion

reduceLeftOPtion

Examples to Implement Scala reduce

Below are the examples mentioned :

Example #1

In this example, we find out the sum of all elements present in the collection data structure using a binary operation.

Code: