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Neo4j Import: java.lang.IllegalStateException: Mixing specified and unspecified group belongings in a single import isn’t supported

I’ve been working with the Neo4j Import Tool recently after a bit of a break and ran into an interesting error message that I initially didn’t understand. I had some CSV files containing nodes that I wanted to import into Neo4j. Their contents look like this: $ cat people_header.csv name:ID(Person)   $ cat people.csv "Mark" "Michael" "Ryan" "Will" "Jennifer" "Karin" ...

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ElasticSearch Tutorial for Beginners

1. Introduction In this example, we shall demonstrate how to make use of Elasticsearch, a distributed free-text search and analysis database engine based on Apache Lucene with a simple maven-based Java client. We will be using the latest version of Elasticsearch, which is ES v6.1.2 while writing this post. For this example we use the following technologies: Maven 3 Java 8 Elasticsearch 6.1.2   ...

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Product Owners need 4 things

To be an effective Product Owner – and that includes product managers and business analysts who are nominating work for teams to do – you need at least four things. You may well need more than these four but these are common across all teams and domains. 1. Skills and experience There is more to being a Product Owner than ...

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Spring @Lazy annotation use cases

spring-interview-questions-answers

The Spring framework with almost no effort can solve for you many common programming problems, but some of its features are less known than others. In this post, we’re going to take a close look at the @Lazy annotation, which belongs to this group. After reading several examples, you should be able to apply the annotation to your daily development ...

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Getting on Board With Blockchain Development

Blockchain has become a new buzzword in Silicon Valley due to its function as a distributed ledger that powers cryptocurrencies and bitcoins. Already, blockchain is making an impact on the programming industry. Financial and technology companies invested $1.4 billion in blockchain technologies in 2016, including a $200 million investment from IBM in a blockchain-powered Internet of Things. The average blockchain ...

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Spring Cloud Stream with Kafka

spring-interview-questions-answers

Overview This sample project demonstrates how to build real-time streaming applications using event-driven architecture, Spring Boot,Spring Cloud Stream, Apache Kafka and Lombok. By the end of this tutorial you’ll have a simple Spring Boot based Greetings micro-service running that takes a message from a REST api writes it to a Kafka topic reads it from the topic outputs it to the console Let’s get started! Btw, you’ll ...

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Using JWT For Sessions

java-interview-questions-answers

The topic has been discussed many times, on hacker news, reddit, blogs. And the consensus is – DON’T USE JWT (for user sessions). And I largely agree with the criticism of typical arguments for the JWT, the typical “but I can make it work…” explanations and the flaws of the JWT standard.. I won’t repeat everything here, so please go ...

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