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Neo4j: How do null values even work?

Every now and then I find myself wanting to import a CSV file into Neo4j and I always get confused with how to handle the various null values that can lurk within. Let’s start with an example that doesn’t have a CSV file in sight. Consider the following list and my attempt to only return null values: WITH [null, "null", ...

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Interview questions: verify the braces

This is one of the easier coding tasks, but you still can meet it in some preliminary tech screening. The problem looks like this: Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" ...

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Going off-heap to improve latency and reduce AWS bill

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Most performance issues can be solved in several different ways. Many of the solutions applicable are well-understood and familiar to most of you. Some solutions, like taking certain data structures off from the JVM-managed heap, are more complex. So if you are not familiar with the concept, I can recommend to proceed to learn how we recently reduced both the ...

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FREE IntelliJ IDEA Licenses Giveaway from Java Code Geeks and JetBrains (total value of $447)!

Looking for a powerful, yet simple, Java IDE ? Then we have something especially for you! We are running a contest giving away 3 FREE licenses for the amazing IntelliJ IDEA IDE. Every aspect of IntelliJ IDEA is specifically designed to maximize developer productivity. Together, powerful static code analysis and ergonomic design make development not only productive but also an ...

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Adventures In Modernization: Strategy + Example Converting COBOL To Java

At Keyhole Software we are in large part a modernization company. We have consultants who specialize in moving old to new, renovating dilapidated code bases, and designing brighter futures for enterprises that have been vendor-locked for most of their existence. As an interesting side effect of these experiences, we have come across some repeated patterns and strategies for how to ...

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Hibernate Caching with HazelCast: Basic configuration

Previously we went through an introduction on JPA caching, the mechanisms and what hibernate offers. What comes next is a hibernate project using Hazelcast as a second level cache. We will use a basic spring boot project for this purpose with JPA. Spring boot uses hibernate as the default JPA provider. Our setup will be pretty close to the one ...

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Hibernate Caching With HazelCast: JPA caching basics

One of the greatest capabilities of HazelCast is the support for hibernate’s second level cache. JPA has two levels of cache. The first level cache caches an object’s state for the duration of a transaction. By querying the same object twice you have to get the object your retrieved the first time. However in case of complex queries which include ...

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Elasticsearch for Java Developers: Introduction

1. Introduction Effective, fast and accurate search functionality is an integral part of vast majority of the modern applications and software platforms. Either you are running a small e-commerce web site and need to offer your customers a search over product catalogs, or you are a service provider and need to expose an API to let the developers filter over ...

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