Most Frequently asked Hazelcast Interview Questions (2020) | TechGeekNext >>





Most Frequently asked Hazelcast Interview Questions (2020)


Hazelcast provides central, predictable scaling of applications through in-memory access to frequently used data and across an elastically scalable data grid. These techniques reduce the query load on databases and improve speed.

  1. Q: What is Hazelcast?
  2. Q: What are the Hazelcast Features?
  3. Q: How to use Hazelcast with Spring Boot?
  4. Q: How does Hazelcast cache works?
  5. Q: What is Hazelcast client?
  6. Q: How does Hazelcast store data?
  7. Q: Is Hazelcast distributed?
  8. Q: How does a Hazelcast distributed map works?
  9. Q: What is Hazelcast multicast?
  10. Q: How to configure the TCP/IP cluster in programmatic way?

In this post, questions from Hazelcast Interviews will be answered for Experienced and Freshers. We're trying to share our experience and learn how to help you make progress in your career.

Q: What is Hazelcast?
Ans:

Hazelcast is the Leading Open Source distributed In-Memory Data Grid based on Java. Hazelcast provides centralized, highly available,consistent scaling of applications by accessing commonly used data in memory and through an elastically scalable data grid. This reduces data base database load and improves efficiency and speed.

Q: What are the Hazelcast Features?
Ans:

  • The data is always stored in-memory (RAM) of the servers.This makes it extremely fast.
  • In case of single or multiple server faults, multiple copies are stored in multiple machines for automated data recovery. In the case of a malfunction, there will be no data loss to the overall cluster.
  • Hazelcast 's major feature is its masterless nature. Every node is designed to be functionally identical, and operates peer-to - peer.
  • The data model is object-oriented and non-relational.
  • Servers can be added or removed dynamically to boost the amount of CPUs and RAMs.
  • The data can be persisted from Hazelcast to a relational or NoSQL database.
  • A Java Map API accesses the distributed key-value store.

Q: How to use Hazelcast with Spring Boot?
Ans:

Hazelcast with Spring Boot Example.

Q: How does Hazelcast cache works?
Ans:

Hazelcast IMDG stores frequently accessed data in memory over an elastically scalable data grid for database caching.It helps any machine network to dynamically cluster and pool all memory and processors to improve performance of applications.

For read-through persistence, Hazelcast asks the loader implementation to load the entry from the data store if an application asks the cache for data but the data is not there.

Through its write-through and write-behind features, Hazelcast can either synchronously or asynchronously propagate any changes in the cached data back into the original store.

Q: What is Hazelcast client?
Ans:

Hazelcast client (com.hazelcast.client.HazelcastClient) allows us to do all Hazelcast operations without being a member of the cluster. It connects to one of the cluster members and delegates all cluster-wide operations to it.

Q: How does Hazelcast store data?
Ans:

Hazelcast recognizes the JSON format in IMap values, so that operations such as predicated queries and aggregations can be run. Hazelcast is scalable horizontally, so you can join hundreds of nodes in a cluster to aggregate terabytes of RAM and hold all of your data in memory.

Q: Is Hazelcast distributed?
Ans:

Hazelcast is a distributed In-Memory Data Grid platform for Java. The architecture supports high scalability and data distribution in a clustered environment.

Q: How does a Hazelcast distributed map works?
Ans:

Hazelcast distributes the map entries onto multiple cluster members. Each member holds some portion of the data. Distributed maps have one backup by default. If a member goes down, your data is recovered using the backups in the cluster.

Q: What is Hazelcast multicast?
Ans:

Hazelcast is a distributed In-Memory Data Grid platform for Java. The architecture supports high scalability and data distribution in a clustered environment.

Q: How to configure the TCP/IP cluster in programmatic way?
Ans:

Config config = new Config();
NetworkConfig networkConfig = config.getNetworkConfig();
networkConfig.setPort(5700).setPortCount(15);
networkConfig.setPortAutoIncrement(true);
JoinConfig join = networkConfig.getJoin();
join.getMulticastConfig().setEnabled(false);
join.getTcpIpConfig()
  .addMember("machineNumber1")
  .addMember("localhost").setEnabled(true);

Hazelcast will try to bind up 100 ports by default. In the above example, if we set the port value to 5700 and limit the port count to 15 as members join the cluster, then Hazelcast is trying to find ports between 5700 and 5715.



















































































Recommendation for Top Popular Post :