Support 7.20

[zambrovski]

Switch examples to latest Camunda Spring Boo, JDK 17..

Steps

• [x] JDK 17
• [x] Spring Boot 3.1.3
• [x] Camunda 7.20
• [x] Camunda 7.20 SQL Scripts
• [x] Polyflow 4.0.0 (4.0.0-SNAPSHOT)
• [x] Camunda BPM Data 1.4.0
• [x] Camunda Platform 7 Mockito 7.20.0
• [x] Axon Server Connector 4.8.2 // FIXME, do we need it?
• [x] SQL sequence per table
• [x] SQL dialect pimping
• [x] OpenAPI genarator (useSpringBoot3)

[lbilger]

My notes for process engine migration to Camunda 7.20 / Polyflow 4 etc. - some notes are specific to our setup (e.g. Azure SQL database), but maybe it helps:

• Update versions in your POM according to the changes above
• Do the javax -> jakarta migration
• If you have a dependency on org.apache.httpcomponents:httpclient, use org.apache.httpcomponents.client5:httpclient5 instead
• If you have a dependency on groovy, change the group id from org.codehaus.groovy to org.apache.groovy
• If you are using the OpenAPI Generator, depending on which generator you use, you might have to set the config options useSpringBoot3 or useJakartaEe to true
• Either migrate your database schema to use DATETIMEOFFSET instead of DATETIME2 for Instants or set spring.jpa.properties.hibernate.type.preferred_instant_jdbc_type to TIMESTAMP in your application.yaml.
• Either migrate your database schema to use UNIQUEIDENTIFIER instead of BINARY for UUIDs or set spring.jpa.properties.hibernate.type.preferred_uuid_jdbc_type to BINARY in your application.yaml.
• Due to a change in how Hibernate handles sequences, you will either need to replace the hibernate_sequence with per-table sequences (recommended) or set the JPA property hibernate.id.db_structure_naming_strategy to legacy to restore the old behavior. An example database script for creating the sequences can be found is attached below

  DECLARE @next_value BIGINT, @sql NVARCHAR(MAX);
  SET @next_value = NEXT VALUE FOR hibernate_sequence;
  SET @sql = 'CREATE SEQUENCE association_value_entry_seq START WITH ' + CAST(@next_value AS NVARCHAR) + ' INCREMENT BY 50'
  EXEC (@sql)
  SET @sql = 'CREATE SEQUENCE domain_event_entry_seq START WITH ' + CAST(@next_value AS NVARCHAR) + ' INCREMENT BY 50'
  EXEC (@sql)
  DROP SEQUENCE hibernate_sequence;

• The database schema upgrade from 7.19 to 7.20 is not very spectacular, but you should apply it nonetheless. Add the scripts to your Flyway migrations directory or whatever you use.