Pouring Coffee into the Matrix: Building Java Applications on Neo4j

Many of us have built applications for traditional data structures (like relational database tables), but is it different for graph data stores? Do developers need to retool and relearn? In this session, we'll cover a brief introduction to graphs, walk you through writing a typical Java application with Spring, and connect it to Neo4j. From interacting with the graph data from the application to deploying to the cloud, you'll see the process from start to finish. You'll also learn how to tackle pitfalls and pick up tips along the way, as well as explore the ways we can build, deploy, and connect applications to the database. This will come alive through a live demo, as we see the results of our efforts. Come to this session to build your business applications for graph data!

Transcript

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
   

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

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3. Developing applications
   

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

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5. Java dev: Why Graph?
   

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

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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;
   }
   

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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 olderVersionDiffs;
   }
   

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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
   

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10. Graph Data Model
    

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

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

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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”
    

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

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15. Relationships
    • Must have a type
    
    • Must have a direction
    
    • May have properties
    JavaVersion
    VersionDiff
    JavaVersion
    version: “17”
    
    
    

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16. Relationships
    • Must have a type
    
    • Must have a direction
    
    • May have properties
    
    • Nodes can share multiple relationships
    JavaVersion
    VersionDiff
    JavaVersion
    version: “17”
    
    
    

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17. Label
    • A group of nodes
    
    • Like a category
    
    • Domain class :)
    Person
    

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18. Label
    • A group of nodes
    
    • Like a category
    
    • Domain class :)
    Person
    Employee
    Customer
    

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19. Properties
    • Key-value pair
    
    • Associated with node or relationship
    
    • Like a variable name and value
    JavaVersion
    JavaVersion
    version: “17”
    version: “6”
    versionSteps: 3
    M
    IG
    RATES
    gaDate: 2021-09-14
    gaDate: 2006-12-12
    codeName: “Mustang”
    

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20. Modeling
    

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21. Whiteboard friendliness
    

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22. Graph data
    

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23. Demo Background
    

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24. Neo4j AuraDB
    • Free tier instance
    
    • Java language version data loaded
    

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25. Language drivers
    • Neo4j Java driver (o
    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
    

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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
    

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27. Let’s see some code!
    Demo time!
    

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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
    

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