Tricky Java Interview Questions and Answers for Experienced Developer | Code Decode | Part - 1

In this video of code decode we have explained tricky java interview questions asked to experienced java developer

Udemy Course of Code Decode on Microservice k8s AWS CICD link:

Course Description Video :

How is WeakHashMap differs from other HashMap?

WeakHashMap is a HashMap, with keys that are of a WeakReference type.

An entry in a WeakHashMap will automatically be removed when its key is no longer in ordinary use, meaning that there is no single Reference that point to that key. When the garbage collection (GC) process discards a key, its entry is effectively removed from the map, even though it is associated with WeakHashMap. i.e Garbage Collector dominates over WeakHashMap.

In HashMap, even if key is not having any reference which points to that key (is eligible for GC) is In reality not eligible for garbage collection because its associated with the entry object added in a bucket of hashMap. This means that the HashMap has dominance over the garbage collector.

What Is ElasticSearch?
Elasticsearch is a NoSQL database.
ElasticSearch is an open source Search Engine based on Apache Lucene as inverted Text Data structure and it is built with RESTful APIS.

We use it for Storing, searching and Managing
Logs
Search Backend with terrific speed and flexibility.

It mainly consist of
Indexes - similar to Database in relational Terms
Documents - Rows - JSON objects
Fields - Columns

It mainly has Read and write operation. you need to update this as soon as you update the main Database and Read it when FE needs Autocomplete feature.

What is Kafka
Apache Kafka is publish-subscribe based fault tolerant messaging system. It is fast, scalable and distributed by design.

It was initially thought of as a message queue and open-sourced by LinkedIn in 2011. Its community evolved Kafka to provide key capabilities:
Publish and Subscribe to streams of records, like a message queue.
Storage system so messages can be consumed asynchronously. Kafka writes data to a scalable disk structure and replicates for fault-tolerance. Producers can wait for write acknowledgments.
Stream processing with Kafka Streams API, enables complex aggregations or joins of input streams onto an output stream of processed data.

Traditional messaging models are queue and publish-subscribe. In a queue, each record goes to one consumer. In publish-subscribe, the record is received by all consumers.

Hibernate Interview Questions and Answers:

Spring Boot Interview Questions and Answers:

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[norbertbaranya]

Just had my technical interview and I feel it went well. I was practicing with your stuff. I wanted to say thank you so much for your effort on making these, it is a huge source of knowledge. Thank you so much!

[stnamelastname]

I m following this channel for 2 years.... Just want to see your faces guys... Getting bored by just hearing you 😂

[sayanbiswas]

I faced some of these questions in real interviews, thanks a lot team ☺️

[sanskaari.]

Thank you so much. Your videos helped me a lot. They taught me so much. You are doing a great job. You give your best whenever you teach. God bless you 😇

[sambhajikale]

I appreciate your efforts for us. Keep motivating us through java tutorials.

[abhrajitnandy]

Yes, need a video related to java 17 features please

[dhanunjaya_]

Oh hoo... that first question, today i was asked in interview. 😅

[sawankundu]

Hello Maam, Can you please make video on Redis cache and Feign Client

[jeet]

Can you also do performance/JVM optimization interview questions.? Thanks 🎉

[arulmozhikarunanidhi]

can you give tech ques for rntcbi it will be helpful

[ChadSigma]

Hi, is this course available for enterprise users yet?

[ganeshturkane]

@Code Decode The course mentioned at start is available on LinkedIn Learning

[cloud_Engineer]

Not able to find this course on udemy business any reason??

[muhassinmusthafa]

Can you pls do versions 9, 11 first if possible ..because most companies are moving from 8 to 9 and 11 nowadays especially 11.
17 also we are waiting..
but even java 8 all features with all possible methods not covered by anyone..a true fact 😃
U can consider it first

[noorahameds]

Many ppl on your udemy course have doubt are asking for help/solution but you don't help on that questions