"No changes found, nothing to do" when generating first changeLog

Hello, I’m currently setting up a project with Liquibase using PostgreSQL and the Hibernate plugin in order to generate the migrations given the created entities. However, when trying to execute the first generateChangeLog, I get the following output:

[INFO] --- liquibase-maven-plugin:3.8.9:generateChangeLog (default-cli) @ townsq ---
[INFO] ------------------------------------------------------------------------
[INFO] Parsing Liquibase Properties File
[INFO]   File: src/main/resources/liquibase.properties
[INFO]   'referenceDriver' in properties file is not being used by this task.
[INFO]   'changeLogFile' in properties file is not being used by this task.
[INFO]   'diffChangeLogFile' in properties file is not being used by this task.
[INFO]   'referenceUrl' in properties file is not being used by this task.
[INFO] ------------------------------------------------------------------------
[INFO] Liquibase Community 3.8.9 by Datical
[INFO] Starting Liquibase at seg, 31 ago 2020 03:13:57 BRT (version 3.8.9 #73 built at Mon Apr 06 09:32:58 UTC 2020)
[INFO] Parsing Liquibase Properties File src/main/resources/liquibase.properties for changeLog parameters
[INFO] Executing on Database: jdbc:postgresql://localhost:5432/TOWNSQ?currentSchema=townsq
[WARNING] Namespace of the [javax.xml.bind.annotation.XmlSchema] annotation does not match [http://www.hibernate.org/xsd/orm/hbm]. Processing bindings will probably fail.
[INFO] Generating Change Log from database devdbuser @ jdbc:postgresql://localhost:5432/TOWNSQ?currentSchema=townsq (Default Schema: townsq)
[INFO] SELECT c.relname AS SEQUENCE_NAME,   s.seqmin AS MIN_VALUE, s.seqmax AS MAX_VALUE, s.seqincrement AS INCREMENT_BY,   s.seqcycle AS WILL_CYCLE, s.seqstart AS START_VALUE, s.seqcache AS CACHE_SIZE,   pg_catalog.format_type(s.seqtypid, NULL) AS SEQ_TYPE FROM pg_class c JOIN pg_namespace ns on c.relnamespace = ns.oid JOIN pg_sequence s on c.oid = s.seqrelid WHERE c.relkind = 'S' AND ns.nspname = 'townsq' AND c.oid not in (select d.objid FROM pg_depend d where d.refobjsubid > 0)
[INFO] src/main/resources/database/db-changelog.xml exists, appending
    SELECT 10 AS max_depth  -- The deeper the recursion goes, the slower it performs.
         , 16384 AS min_oid -- user objects only
         , '^(londiste|pgq|pg_toast)'::text AS schema_exclusion
         , '^pg_(conversion|language|ts_(dict|template))'::text AS class_exclusion
         , '{"SCHEMA":"00", "TABLE":"01", "CONSTRAINT":"02", "DEFAULT":"03",
      "INDEX":"05", "SEQUENCE":"06", "TRIGGER":"07", "FUNCTION":"08",
      "VIEW":"10", "MVIEW":"11", "FOREIGN":"12"}'::json AS type_ranks),
               dependency_pair AS (
                   WITH relation_object AS ( SELECT oid, oid::regclass::text AS object_name  FROM pg_class )
                   SELECT DISTINCT                          substring(pg_identify_object(classid, objid, 0)::text, E'(\\w+?)\\.') as referenced_schema_name,                          CASE classid
                              WHEN 'pg_attrdef'::regclass THEN (SELECT attname FROM pg_attrdef d JOIN pg_attribute c ON (c.attrelid,c.attnum)=(d.adrelid,d.adnum) WHERE d.oid = objid)
                              WHEN 'pg_cast'::regclass THEN (SELECT concat(castsource::regtype::text, ' AS ', casttarget::regtype::text,' WITH ', castfunc::regprocedure::text) FROM pg_cast WHERE oid = objid)
                              WHEN 'pg_class'::regclass THEN rel.object_name
                              WHEN 'pg_constraint'::regclass THEN (SELECT conname FROM pg_constraint WHERE oid = objid)
                              WHEN 'pg_extension'::regclass THEN (SELECT extname FROM pg_extension WHERE oid = objid)
                              WHEN 'pg_namespace'::regclass THEN (SELECT nspname FROM pg_namespace WHERE oid = objid)
                              WHEN 'pg_opclass'::regclass THEN (SELECT opcname FROM pg_opclass WHERE oid = objid)
                              WHEN 'pg_operator'::regclass THEN (SELECT oprname FROM pg_operator WHERE oid = objid)
                              WHEN 'pg_opfamily'::regclass THEN (SELECT opfname FROM pg_opfamily WHERE oid = objid)
                              WHEN 'pg_proc'::regclass THEN objid::regprocedure::text
                              WHEN 'pg_rewrite'::regclass THEN (SELECT ev_class::regclass::text FROM pg_rewrite WHERE oid = objid)
                              WHEN 'pg_trigger'::regclass THEN (SELECT tgname FROM pg_trigger WHERE oid = objid)
                              WHEN 'pg_type'::regclass THEN objid::regtype::text
                              ELSE objid::text
                              END AS REFERENCED_NAME,
                          substring(pg_identify_object(refclassid, refobjid, 0)::text, E'(\\w+?)\\.') as referencing_schema_name,                           CASE refclassid
                              WHEN 'pg_namespace'::regclass THEN (SELECT nspname FROM pg_namespace WHERE oid = refobjid)
                              WHEN 'pg_class'::regclass THEN rrel.object_name
                              WHEN 'pg_opfamily'::regclass THEN (SELECT opfname FROM pg_opfamily WHERE oid = refobjid)
                              WHEN 'pg_proc'::regclass THEN refobjid::regprocedure::text
                              WHEN 'pg_type'::regclass THEN refobjid::regtype::text
                              ELSE refobjid::text
                              END AS REFERENCING_NAME
                   FROM pg_depend dep
                            LEFT JOIN relation_object rel ON rel.oid = dep.objid
                            LEFT JOIN relation_object rrel ON rrel.oid = dep.refobjid, preference
                   WHERE deptype = ANY('{n,a}')
                     AND objid >= preference.min_oid
                     AND (refobjid >= preference.min_oid OR refobjid = 2200) -- need public schema as root node
                     AND classid::regclass::text !~ preference.class_exclusion
                     AND refclassid::regclass::text !~ preference.class_exclusion
                     AND COALESCE(SUBSTRING(objid::regclass::text, E'^(\\\\w+)\\\\.'),'') !~ preference.schema_exclusion
                     AND COALESCE(SUBSTRING(refobjid::regclass::text, E'^(\\\\w+)\\\\.'),'') !~ preference.schema_exclusion
                   GROUP BY classid, objid, refclassid, refobjid, deptype, rel.object_name, rrel.object_name
 select referenced_schema_name,
      WHEN position('.' in referenced_name) >0 THEN substring(referenced_name from position('.' in referenced_name)+1 for length(referenced_name))
      ELSE referenced_name
    END)  AS referenced_name, 
      WHEN position('.' in referencing_name) >0 THEN substring(referencing_name from position('.' in referencing_name)+1 for length(referencing_name))
      ELSE referencing_name
    END)  AS referencing_name from dependency_pair where REFERENCED_NAME != REFERENCING_NAME  AND ( REFERENCED_NAME like 'townsq.%' OR REFERENCED_NAME NOT LIKE '%.%')  AND referencing_schema_name is not null and referencing_name is not null
[INFO] No changes found, nothing to do
[INFO] Output written to Change Log file, src/main/resources/database/db-changelog.xml

Update: now it’s detecting the entities, but I’m getting the following error:

[ERROR] Failed to execute goal org.liquibase:liquibase-maven-plugin:3.8.9:diff (default-cli) on project townsq: Execution default-cli of goal org.liquibase:liquibase-maven-plugin:3.8.9:diff failed: A required class was missing while executing org.liquibase:liquibase-maven-plugin:3.8.9:diff: liquibase/util/StringUtil