How to prevent singleton class from Reflection | serialization | Cloning | Java Techie

  Рет қаралды 37,121

Java Techie

Java Techie

Күн бұрын

Пікірлер: 74
@nandkishorwankhade8012
@nandkishorwankhade8012 Ай бұрын
You are just amazing as usual, thanks for crisps explanation.😊
@saumitrasaxena8470
@saumitrasaxena8470 2 жыл бұрын
Hi , First of all congrats for good explanation . I did more deeper analysis into it and can see this code can also break. Let's see how. Suppose we create 2 Threads . Thread-1 calls getInstance() and reaches line 21 , and now 2nd Thread I used reflection code and new Object is created via constructor as instance is still null. And now again when line 21 is executed ,new instance is created again.So two object is created.
@iltwrrm
@iltwrrm 6 ай бұрын
thanks Java Techie. I love your videos and how you enhance our understanding about concepts such as this, creating a Singleton, and then breaking it; really helps our understanding and furthers our comprehension and knowledge. love it. keep ‘em coming
@parthdalvi5855
@parthdalvi5855 8 ай бұрын
Thank you for sharing this. Its really easy to understand.
@dineshkumar-lf2vk
@dineshkumar-lf2vk 3 жыл бұрын
bhai maza hi tumari videos ko dekhne me aata h. Hindi
@jibandeepbal1639
@jibandeepbal1639 3 жыл бұрын
Very well explained. Thank you for sharing your knowledge.
@myakhandbharat-2024
@myakhandbharat-2024 Жыл бұрын
Very good Information Man 🙂.
@kumarinidhi90
@kumarinidhi90 2 жыл бұрын
wonderful and knowledgeable video.. Really understood the concepts and it is very useful video. I have a request, please make a similar series for JavaScript interview questions and a similar series for react js interview questions ..
@balajibollu7197
@balajibollu7197 6 ай бұрын
super thanks bro sharing for knowledge
@swathiallu9819
@swathiallu9819 4 жыл бұрын
Very good explanation. Its clean and clear. Thanks
@RAVI_GIT
@RAVI_GIT 2 жыл бұрын
Excellent Idea
@ramanareddysagili3626
@ramanareddysagili3626 2 жыл бұрын
Outstanding man
@sushilrajiwade3551
@sushilrajiwade3551 3 жыл бұрын
Very Nice Explanation!!! Thank You
@tulasiramsunkara
@tulasiramsunkara 3 жыл бұрын
Excellent explanation
@sumannagella5034
@sumannagella5034 5 жыл бұрын
hi sir thanks for posting very useful videos, please post some other most important concepts of real time and also some more important design patterns. so that it will be helpful for lot of developers
@Javatechie
@Javatechie 5 жыл бұрын
Ok will do it suman
@nagarajanerode
@nagarajanerode 3 жыл бұрын
Good explanations
@cvarun9221
@cvarun9221 3 жыл бұрын
WATCH @ 1.5x speed, save time. Thanks !
@AmitGadaley17
@AmitGadaley17 3 жыл бұрын
Very useful and well explained!!
@abhrajitnandy
@abhrajitnandy Жыл бұрын
For reflection case: can we return the same instance instead of throwing exception? Like how in readResolve()
@Javatechie
@Javatechie Жыл бұрын
But how can we return from the constructor buddy
@abhrajitnandy
@abhrajitnandy Жыл бұрын
@@Javatechie Oh ! My bad.
@Javatechie
@Javatechie Жыл бұрын
@abhrajitnandy no problem
@bhaktilatadash7619
@bhaktilatadash7619 3 жыл бұрын
Nice explanation..Thank u
@maheshguptatallada6015
@maheshguptatallada6015 2 жыл бұрын
Hi Sir, @Java Techie Could you please clarify the below. when IllegalArgumentException is runTime one, why the compiler is asking us to throw it in compile time in this code ?
@858Bikash
@858Bikash 2 жыл бұрын
Thank you sir🙏🙏
@greentorainchannel386
@greentorainchannel386 2 жыл бұрын
Hello Sir, Thank you for detailed info on Singleton pattern. I have a question Sir, don't we need to add null check in readResolve() method? Could you please help in clarifying this Sir?
@Javatechie
@Javatechie 2 жыл бұрын
No readResolve only called at the time of deserialize so here we want to return the existing instance . that's why no null check required here
@SanjeevKulkarniWorld
@SanjeevKulkarniWorld 4 жыл бұрын
Good work 👍
@muttaiahv2328
@muttaiahv2328 2 жыл бұрын
could you pease do the video for all other design patterns sir that would help us to understand the importance of various design patterns .
@Javatechie
@Javatechie 2 жыл бұрын
Will do that
@sameerpatere2983
@sameerpatere2983 5 жыл бұрын
Thank you, sir. Nice explanation
@manjosh1990
@manjosh1990 5 жыл бұрын
Can you also show how to break it using classloaders and how to avoid it.
@palaniappanrm6277
@palaniappanrm6277 5 жыл бұрын
Hi, let's say we export these classes as a jar to other clients. They didn't create any Singleton objects yet. They have a file that has our singleton object serialized. When they read the file and try to deserialize it, this readResolve method will get called and will return instance which is pointing to null. I think we should have a null check in the readResolve method. Right?
@Javatechie
@Javatechie 5 жыл бұрын
You are correct in lazy Singleton approach we should add null check but if it is eager Singleton approach the Then it's not required . Because on class level we are creating instance in eager loading Singleton approach
@palaniappanrm6277
@palaniappanrm6277 5 жыл бұрын
@@Javatechie I was pointing to lazy load approach only. Thanks.
@saumitrasaxena8470
@saumitrasaxena8470 2 жыл бұрын
if I create an object using reflection first -- I will have one object as first-time instance is null so object is created using reflection and 2nd time i call getInstance then I will get object created by reflection ....Am i correct ?
@maan9011
@maan9011 5 жыл бұрын
Superb
@chetankhandave1072
@chetankhandave1072 Жыл бұрын
Is it better to make static variable as volatile ?
@kishorekumar2554
@kishorekumar2554 2 жыл бұрын
Thank you
@preetird8385
@preetird8385 4 жыл бұрын
Good explanation. Thank you 👍
@kishordige4654
@kishordige4654 2 жыл бұрын
Thanks Man
@sarikagarg8185
@sarikagarg8185 3 жыл бұрын
Can we use transient keyword at declaration place of instance. So that object creation due to serialisation could be avoided
@Javatechie
@Javatechie 3 жыл бұрын
Serialization never create object . Object can be created using deserialization
@sarikagarg8185
@sarikagarg8185 3 жыл бұрын
@@Javatechie but if objects are not mapped in file then how deserialization will do anything ?
@Javatechie
@Javatechie 3 жыл бұрын
Can we perform deserialization from only file ?
@sarikagarg8185
@sarikagarg8185 3 жыл бұрын
@@Javatechie As per the code you shown a serialization is done in a file. I also have a query that once a class is created which don't extends to myclone and don't implements serelizable interface the how some othe program would be able to make clone out of that class
@Javatechie
@Javatechie 3 жыл бұрын
Let's say your singleton class extends from some other class and that class extends from Serializable then in that situation anyone can deserilize your singleton class right ?
@priyankawagh5217
@priyankawagh5217 4 жыл бұрын
Perfect!
@mohammadmujahid8850
@mohammadmujahid8850 5 жыл бұрын
ultimate.
@minatimahapatra4182
@minatimahapatra4182 5 жыл бұрын
hi Sir. I have tried with implementing Cloneable(I) in LazySingleton class and worked fine with breaking Singleton behaviour. So why should we go for MYClone class.
@Javatechie
@Javatechie 5 жыл бұрын
In some worst senario we may need my class to be extends from some other class .so In such case if that class implement Clonable then it will break the rules . So for demonstrate purpose I created this MyClone class
@saurabhkailashchandrapuran8609
@saurabhkailashchandrapuran8609 3 жыл бұрын
Basant sir plz make more videos on interview question like circular dependency on beans and many more which you think will be help in interview.
@Javatechie
@Javatechie 3 жыл бұрын
Okay I will
@rabindrakumar949
@rabindrakumar949 5 жыл бұрын
Without throwing exception we should return the same object. With this the applications won't break because of exception.
@Javatechie
@Javatechie 5 жыл бұрын
Yes we can
@satishkumar1799
@satishkumar1799 5 жыл бұрын
How can we avoid breaking singleton in case of multiple jvms... May be load balancing case...
@Javatechie
@Javatechie 5 жыл бұрын
Singleton can't be safe in multiple JVM . Singleton : one instance per JVM
@satishkumar1799
@satishkumar1799 5 жыл бұрын
@@Javatechie Thanks for ur response... can u plzz upload end to end spring rest service based app which maintenance user session using basic authentication..
@Javatechie
@Javatechie 5 жыл бұрын
@@satishkumar1799 yeah sure will upload
@satishkumar1799
@satishkumar1799 5 жыл бұрын
@@Javatechie Thank You!
@anirudhjadhav9663
@anirudhjadhav9663 3 жыл бұрын
But bro! If you create an object by using the reflection first and second the getInstance then you will end with two instances.
@Javatechie
@Javatechie 3 жыл бұрын
That's the reason constructor level itself I added null check
@anirudhjadhav9663
@anirudhjadhav9663 3 жыл бұрын
@@Javatechie Can you try this code:- LazySingleton reflectionInstance = null; Class clazz = Class.forName("LazySingleton "); Constructor s3Constructor = clazz.getDeclaredConstructor(); s3Constructor.setAccessible(true); reflectionInstance = s3Constructor.newInstance(); System.out.println("Reflection hashcode :- " + reflectionInstance .hashCode()); LazySingleton instance1 = LazySingleton.getInstance(); System.out.println("Instance hashcode :- " + instance1.hashCode());
@sumansatpathy2862
@sumansatpathy2862 2 жыл бұрын
@@anirudhjadhav9663 Just saw your comments & I had also same doubt. Tried to solve. Could you please check this below sol if that works. Please let me know if you find any catch here. private static boolean isCallFromMyGetInstance = false; private static MySingletonClass obj; private MySingletonClass(){ if(obj!=null || isCallFromMyGetInstance==false) { throw new IllegalStateException("Object can't be created using reflection for this class"); } } public static MySingletonClass getInstance() { if(obj==null) { synchronized (MySingletonClass.class) { if(obj==null) isCallFromMyGetInstance=true; obj=new MySingletonClass(); } } return obj; }
@AmritAgarwal07
@AmritAgarwal07 2 жыл бұрын
1 more way is interfaces and enum also singletons[i].reference = new Singleton();
@saurabhpatil2156
@saurabhpatil2156 Жыл бұрын
I can still break your singleton code by executing reflection first and calling getInstance() later. I will have 2 objects of your class
JDK 13 : The new features in Java 13 | Example | Java Techie
16:54
SOLID Design Principles in java with Example | JavaTechie
34:44
Java Techie
Рет қаралды 194 М.
Когда отец одевает ребёнка @JaySharon
00:16
История одного вокалиста
Рет қаралды 16 МЛН
Family Love #funny #sigma
00:16
CRAZY GREAPA
Рет қаралды 14 МЛН
13. Java Singleton and Immutable Class Explained with Examples | Java Classes in Depth - Part4
28:26
Java 8 Streams | Optional Usage and Best Practices | JavaTechie
22:22
The Singleton Design Pattern - Part of the Gang of Four
28:41
IAmTimCorey
Рет қаралды 76 М.