This document introduces Jennifer Reif and discusses using Java applications with Neo4j. It describes Jennifer's background and roles. It then explains the options for using a relational database or graph database with Java applications. It introduces property graphs and shows an example domain model for Java versions and relationships. Finally, it discusses using Spring Data Neo4j to connect Java applications to Neo4j and demonstrates some code.

1. Jennifer Reif
Email: jennifer.reif@neo4j.com
Twitter: @JMHReif
LinkedIn: linkedin.com/in/jmhreif
Github: GitHub.com/JMHReif
Website: jmhreif.com
Pouring Coffee into the Matrix
Building Java applications on Neo4j

2. Who Am I?
• Developer + Advocate
• Continuous learner
• Technical content writer
• Conference speaker
• Other: geek

3. Developing applications

4. Java App Data Store Options
• Relational
• Straight JDBC
• JDBC Template
• JOOQ
• JPA or Hibernate
• NoSQL - Document
• MongoDB
• Graph
• Neo4j

5. Java dev: Why Graph?

6. Java domain
• Java Versions (i.e. 8, 11, 17)
• Changes between versions over time
• Di
ff
s

7. Java Entity - Domain Class
• Class
• Entity/Object
• Represents domain type
• General outline for objects of that type
• Variables/Properties
• Details for that entity
• Values may not always exist
• Constructor - instance of object
• Each instance is unique object with varying info
@Node
@Data
@RequiredArgsConstructor
public class JavaVersion {
@Id
@Property("version")
private
fi
nal String javaVersion;
private String name, codeName, status, apiSpec;
private LocalDate gaDate, eolDate;
}

8. Java Domain Relationships
• Adding relationships
• Add variable as pointer to another object
• Links entities together
• Might have some annotations for mapping
@Node
@Data
@RequiredArgsConstructor
public class JavaVersion {
@Relationship(“FROM_NEWER”)
private List<VersionDiff> olderVersionDiffs;
}

9. • Set theory - rows and columns
• Schema - rigid, enforced
• Entities - table row
• Metadata - columns
• Relationships - crafted JOINs
• Queries - JOINs at runtime
• Indexes - Lookups scans
Graphs for Java devs
• Graph theory - entity network
• Schema -
fl
exible, optional
• Entities - node (object)
• Metadata - properties
• Relationships - stored joins
• Queries - joins at write
• Indexes - place to start
Relational database Graph database

10. Graph Data Model

11. Property Graph
• Node (vertex)
• Relationship (edge)

12. Nodes
• Represent objects or entities
• Can be labeled
JavaVersion
VersionDiff
JavaVersion

13. Nodes
• Represent objects or entities
• Can be labeled
• May have properties
JavaVersion
VersionDiff
JavaVersion
version: “17”
gaDate: 2021-09-14
fromVersion: “17.0.3+7-tem”
toVersion: “1.6.0_45-oracle”
version: “6”
gaDate: 2006-12-12
codeName: “Mustang”

14. Relationships
• Must have a type
• Must have a direction
JavaVersion
VersionDiff
JavaVersion
version: “17”

25. ffi
cial)
• Spring Data Neo4j
• Uses Neo4j Java driver at base
• Other options:
• O
ffi
cial drivers-> Python, JavaScript, Go, .NET
• Java frameworks-> Quarkus, Helidon, Micronaut, etc

26. Spring provisions
• Spring Initializr
• Spring Boot’s reduction of boilerplate
• Annotation-based OGM for POJOs
• Query derivation + DSL for custom (Cypher)
• Spring Data’s easy connection to Neo4j
• BOLT or HTTP

27. Let’s see some code!
Demo time!

28. Resources
• Source code: github.com/JMHReif/pouring-co
ff
ee-into-matrix-lombok
• Spring Data Neo4j documentation: dev.neo4j.com/sdn-docs
• Neo4j AuraDB: bit.ly/neo4j-aura
• Blog: bit.ly/jmhreif-blog
Jennifer Reif
Email: jennifer.reif@neo4j.com
Twitter: @JMHReif
LinkedIn: linkedin.com/in/jmhreif
Github: GitHub.com/JMHReif
Website: jmhreif.com