generateChangeLog reports success but no changes listed

I’m trying to run generateChangeLog on an existing derby database. It has a number of tables in it.

c:\Projects\core\cams>java -jar lib\liquibase.jar --classpath=derby.jar;derbyclient.jar --driver=org.apache.derby.jdbc.EmbeddedDriver --url=“jdbc:derby:CAMSDB” --changeLogFile=db-changelog.xml --logLevel=debug --logFile=log.txt generateChangelog

The resulting output indicates success:

INFO 13/03/15 14:27: liquibase: Can not use class liquibase.serializer.core

.json.JsonChangeLogSerializer as a Liquibase service because org.yaml.snake

yaml.representer.Representer is not in the classpath

INFO 13/03/15 14:27: liquibase: Can not use class liquibase.serializer.core

.yaml.YamlChangeLogSerializer as a Liquibase service because org.yaml.snake

yaml.representer.Representer is not in the classpath

Liquibase ‘generateChangelog’ Successful

The debug trace is:

DEBUG 13/03/15 14:27: liquibase: Connected to APP@jdbc:derby:CAMSDB

DEBUG 13/03/15 14:27: liquibase: Setting auto commit to false from true

DEBUG 13/03/15 14:27: liquibase: Executing QUERY database command: select current schema from sysibm.sysdummy1

DEBUG 13/03/15 14:27: liquibase: Computed checksum for 1426256831398 as 0815fc1f3d5660bee0ff4ef70e42471d

INFO 13/03/15 14:27: liquibase: db-changelog.xml does not exist, creating

DEBUG 13/03/15 14:27: liquibase: MissingObjectChangeGenerator type order: liquibase.structure.core.Catalog liquibase.structure.core.Schema liquibase.structure.core.Sequence liquibase.structure.core.StoredProcedure liquibase.structure.core.Table liquibase.structure.core.Column liquibase.structure.core.PrimaryKey liquibase.structure.core.UniqueConstraint liquibase.structure.core.ForeignKey liquibase.structure.core.Index liquibase.structure.core.View

DEBUG 13/03/15 14:27: liquibase: UnexpectedObjectChangeGenerator type order: liquibase.structure.core.Catalog liquibase.structure.core.ForeignKey liquibase.structure.core.Schema liquibase.structure.core.StoredProcedure liquibase.structure.core.UniqueConstraint liquibase.structure.core.View liquibase.structure.core.Table liquibase.structure.core.PrimaryKey liquibase.structure.core.Column liquibase.structure.core.Index liquibase.structure.core.Sequence

DEBUG 13/03/15 14:27: liquibase: ChangedObjectChangeGenerator type order: liquibase.structure.core.Catalog liquibase.structure.core.ForeignKey liquibase.structure.core.Schema liquibase.structure.core.Sequence liquibase.structure.core.StoredProcedure liquibase.structure.core.Table liquibase.structure.core.Column liquibase.structure.core.PrimaryKey liquibase.structure.core.Index liquibase.structure.core.UniqueConstraint liquibase.structure.core.View

INFO 13/03/15 14:27: liquibase: Shutting down derby connection: jdbc:derby:CAMSDB;shutdown=true

but the created xml file is substantially empty

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<databaseChangeLog xmlns=“http://www.liquibase.org/xml/ns/dbchangelog” xmlns:ext=“http://www.liquibase.org/xml/ns/dbchangelog-ext” xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance” xsi:schemaLocation=“http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.3.xsd http://www.liquibase.org/xml/ns/dbchangelog-ext http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd”/>

Why is it not working?