liquibase:diff command throws Null pointer exception

I generated liquibase schema with mvn liquibase:generateChangeLog, and when I try to execute the diff command with mvn liquibase:diff I get an error message Error getting default schema java.lang.NullPointerException. Not sure what's wrong with my configuration. I am testing Liquibase 3.6 with Spring Boot and Spring JPA

Error Message

 mvn liquibase:diff
[INFO] Scanning for projects...
[INFO] 
[INFO] -------------------------< com:liquibasetest >--------------------------
[INFO] Building liquibasetest 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- liquibase-maven-plugin:3.6.3:diff (default-cli) @ liquibasetest ---
[INFO] ------------------------------------------------------------------------
[INFO] Parsing Liquibase Properties File
[INFO]   File: src/main/resources/liquibase.properties
[INFO]   'outputChangeLogFile' in properties file is not being used by this task.
[INFO] ------------------------------------------------------------------------
[INFO] Starting Liquibase at Tue, 12 Feb 2019 00:05:05 EST (version 3.6.3 built at 2019-01-29 11:34:48)
[WARNING] Can not use class liquibase.ext.hibernate.database.HibernateSpringDatabase as a Liquibase service because org.springframework.beans.factory.support.BeanDefinitionRegistry is not in the classpath
[INFO] Executing on Database: jdbc:mysql://localhost:3306/flywaytest?currentSchema=flywaytest
[WARNING] Unknown database: Hibernate
[INFO] Performing Diff on database root@localhost @ jdbc:mysql://localhost:3306/flywaytest?currentSchema=flywaytest (Default Schema: flywaytest)
[INFO] Error getting default schema
java.lang.NullPointerException
    at liquibase.executor.jvm.JdbcExecutor$QueryCallableStatementCallback.doInCallableStatement (JdbcExecutor.java:452)
    at liquibase.executor.jvm.JdbcExecutor.execute (JdbcExecutor.java:93)
    at liquibase.executor.jvm.JdbcExecutor.query (JdbcExecutor.java:135)
    at liquibase.executor.jvm.JdbcExecutor.query (JdbcExecutor.java:146)
    at liquibase.executor.jvm.JdbcExecutor.queryForObject (JdbcExecutor.java:154)
    at liquibase.executor.jvm.JdbcExecutor.queryForObject (JdbcExecutor.java:169)
    at liquibase.executor.jvm.JdbcExecutor.queryForObject (JdbcExecutor.java:164)
    at liquibase.database.AbstractJdbcDatabase.getConnectionSchemaName (AbstractJdbcDatabase.java:327)
    at liquibase.database.AbstractJdbcDatabase.getDefaultSchemaName (AbstractJdbcDatabase.java:292)
    at liquibase.CatalogAndSchema.customize (CatalogAndSchema.java:151)
    at liquibase.snapshot.SnapshotGeneratorFactory.createSnapshot (SnapshotGeneratorFactory.java:184)
    at liquibase.command.core.DiffCommand.createReferenceSnapshot (DiffCommand.java:221)
    at liquibase.command.core.DiffCommand.createDiffResult (DiffCommand.java:143)
    at liquibase.command.core.DiffToChangeLogCommand.run (DiffToChangeLogCommand.java:51)
    at liquibase.command.AbstractCommand.execute (AbstractCommand.java:19)
    at liquibase.integration.commandline.CommandLineUtils.doDiffToChangeLog (CommandLineUtils.java:237)
    at liquibase.integration.commandline.CommandLineUtils.doDiffToChangeLog (CommandLineUtils.java:212)
    at org.liquibase.maven.plugins.LiquibaseDatabaseDiff.performLiquibaseTask (LiquibaseDatabaseDiff.java:177)
    at org.liquibase.maven.plugins.AbstractLiquibaseMojo.execute (AbstractLiquibaseMojo.java:366)
    at org.liquibase.maven.plugins.LiquibaseDatabaseDiff.execute (LiquibaseDatabaseDiff.java:136)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:956)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:288)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:192)
    at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:498)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:289)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:229)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:415)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:356)
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  3.773 s
[INFO] Finished at: 2019-02-12T00:05:07-05:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.liquibase:liquibase-maven-plugin:3.6.3:diff (default-cli) on project liquibasetest: Error setting up or running Liquibase: liquibase.command.CommandExecutionException: java.lang.NullPointerException -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

liquibase.properties

outputChangeLogFile= src/main/resources/db/db.changelog-master.xml
driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/flywaytest?currentSchema=flywaytest
username=root
password=bcmc1234

db.changlog-master.xml

<?xml version="1.1" 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-ext http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.6.xsd">
    <changeSet author="pjadda (generated)" id="1549947881457-1">
        <createTable tableName="country">
            <column name="id" type="BIGINT">
                <constraints primaryKey="true"/>
            </column>
            <column name="name" type="VARCHAR(45)"/>
            <column name="code" type="VARCHAR(45)"/>
            <column name="iso_code" type="VARCHAR(45)"/>
            <column name="region_id" type="BIGINT"/>
        </createTable>
    </changeSet>
    <changeSet author="pjadda (generated)" id="1549947881457-2">
        <createTable tableName="region">
            <column name="id" type="BIGINT">
                <constraints primaryKey="true"/>
            </column>
            <column name="name" type="VARCHAR(45)"/>
        </createTable>
    </changeSet>
    <changeSet author="pjadda (generated)" id="1549947881457-3">
        <createIndex indexName="region_fk_idx" tableName="country">
            <column name="region_id"/>
        </createIndex>
    </changeSet>
    <changeSet author="pjadda (generated)" id="1549947881457-4">
        <addForeignKeyConstraint baseColumnNames="region_id" baseTableName="country" constraintName="region_fk" deferrable="false" initiallyDeferred="false" onDelete="NO ACTION" onUpdate="NO ACTION" referencedColumnNames="id" referencedTableName="region" validate="true"/>
    </changeSet>
</databaseChangeLog>

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com</groupId>
    <artifactId>liquibasetest</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>liquibasetest</name>
    <description>Liquibase Test project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-boot.version>2.1.1.RELEASE</spring-boot.version>
        <spring-boot-admin.version>2.1.1</spring-boot-admin.version>
        <hibernate.version>5.4.0.Final</hibernate.version>
        <liquibase-maven-plugin.version>3.6.3</liquibase-maven-plugin.version>
        <liquibase-hibernate5.version>3.6</liquibase-hibernate5.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-envers</artifactId>
            <version>${hibernate.version}</version>
        </dependency>
        <dependency>
            <groupId>org.liquibase</groupId>
            <artifactId>liquibase-core</artifactId>
        </dependency>
        <dependency>
            <groupId>org.liquibase</groupId>
            <artifactId>liquibase-maven-plugin</artifactId>
            <version>${liquibase-maven-plugin.version}</version>
        </dependency>


        <dependency>
            <groupId>de.codecentric</groupId>
            <artifactId>spring-boot-admin-starter-client</artifactId>
        </dependency>
        <dependency>
            <groupId>de.codecentric</groupId>
            <artifactId>spring-boot-admin-starter-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
<!--        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>de.codecentric</groupId>
                <artifactId>spring-boot-admin-dependencies</artifactId>
                <version>${spring-boot-admin.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>

            <plugin>
                <groupId>org.liquibase</groupId>
                <artifactId>liquibase-maven-plugin</artifactId>
                <version>${liquibase-maven-plugin.version}</version>
                <configuration>
                    <propertyFile>src/main/resources/liquibase.properties</propertyFile>
                    <changeLogFile>src/main/resources/db/db.changelog-master.xml</changeLogFile>
                    <diffChangeLogFile>src/main/resources/db/changelog/${maven.build.timestamp}_changelog.xml</diffChangeLogFile>
                    <logging>info</logging>
                </configuration>
  <!--              <executions>
                    <execution>
                        <id>generate-db-prev</id>
                        <phase>process-resources</phase>
                        <goals>
                            <goal>update</goal>
                        </goals>
                        <configuration>
                            <dropFirst>true</dropFirst>
                        </configuration>
                    </execution>
                    <execution>
                        <id>generate-db-diff</id>
                        <phase>process-test-resources</phase>
                        <goals>
                            <goal>diff</goal>
                        </goals>
                    </execution>
                </executions>-->
                <dependencies>
                    <dependency>
                        <groupId>org.liquibase.ext</groupId>
                        <artifactId>liquibase-hibernate4</artifactId>
                        <version>3.6</version>
                    </dependency>
                </dependencies>

            </plugin>
        </plugins>
    </build>

</project>

Solution

Update: As of 03-Jun-2019 latest liquibase version 3.6.3 and liquibase-hibernate5 plugin version 3.7 have a bug and will update the post once it's resolved. Meanwhile, use liquibase-maven-plugin version 3.5.5 and liquibase-hibernate5 version 3.6

Solution:

I figured out the issue. Spring JPA uses Hibernate 5.x and I configured liquibase-hibernate4 in liquibase dependencies. Thanks to Steve Donnie for pointing out the warning message. Changing liquibase version created another exception related Spring JPA, so I moved Spring JPA dependency to liquibase dependencies and added validation-api dependency to prevent validation errors

            <dependencies>
                <dependency>
                    <groupId>org.liquibase.ext</groupId>
                    <artifactId>liquibase-hibernate5</artifactId>
                    <version>${liquibase-hibernate5.version}</version>
                </dependency>
                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-data-jpa</artifactId>
                    <version>${spring-boot.version}</version>
                </dependency>
                <dependency>
                    <groupId>javax.validation</groupId>
                    <artifactId>validation-api</artifactId>
                    <version>${validation-api.version}</version>
                </dependency>
            </dependencies>

so updated pom.xml is as below

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com</groupId>
    <artifactId>liquibasetest</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>liquibasetest</name>
    <description>Liquibase Test project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-boot.version>2.1.2.RELEASE</spring-boot.version>
        <spring-boot-admin.version>2.1.1</spring-boot-admin.version>
        <hibernate.version>5.4.0.Final</hibernate.version>
        <liquibase-maven-plugin.version>3.5.5</liquibase-maven-plugin.version>
        <liquibase-hibernate5.version>3.6</liquibase-hibernate5.version>
        <validation-api.version>2.0.1.Final</validation-api.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>


        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-envers</artifactId>
            <version>${hibernate.version}</version>
        </dependency>

        <dependency>
            <groupId>de.codecentric</groupId>
            <artifactId>spring-boot-admin-starter-client</artifactId>
        </dependency>
        <dependency>
            <groupId>de.codecentric</groupId>
            <artifactId>spring-boot-admin-starter-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>org.liquibase</groupId>
            <artifactId>liquibase-core</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.liquibase</groupId>
            <artifactId>liquibase-maven-plugin</artifactId>
            <version>${liquibase-maven-plugin.version}</version>
        </dependency>



        <!--        <dependency>
                    <groupId>com.h2database</groupId>
                    <artifactId>h2</artifactId>
                    <scope>runtime</scope>
                </dependency>-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>de.codecentric</groupId>
                <artifactId>spring-boot-admin-dependencies</artifactId>
                <version>${spring-boot-admin.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>

            <plugin>
                <groupId>org.liquibase</groupId>
                <artifactId>liquibase-maven-plugin</artifactId>
                <version>${liquibase-maven-plugin.version}</version>
                <configuration>
                    <propertyFile>src/main/resources/liquibase.properties</propertyFile>
                    <changeLogFile>src/main/resources/db/db.changelog-master.xml</changeLogFile>
                    <diffChangeLogFile>src/main/resources/db/changelog/${maven.build.timestamp}_changelog.xml</diffChangeLogFile>
                    <logging>debug</logging>
                </configuration>
                <dependencies>
                    <dependency>
                        <groupId>org.liquibase.ext</groupId>
                        <artifactId>liquibase-hibernate5</artifactId>
                        <version>${liquibase-hibernate5.version}</version>
                    </dependency>
                    <dependency>
                        <groupId>org.springframework.boot</groupId>
                        <artifactId>spring-boot-starter-data-jpa</artifactId>
                        <version>${spring-boot.version}</version>
                    </dependency>
                    <dependency>
                        <groupId>javax.validation</groupId>
                        <artifactId>validation-api</artifactId>
                        <version>${validation-api.version}</version>
                    </dependency>
                </dependencies>

            </plugin>
        </plugins>
    </build>

</project>