Maven + Spring + Hibernate: hibernate3-maven-plugin hbm2ddl fails for reason "Caused by: java.lang.NullPointerException"
hbm2ddl, hibernate, hibernate3-maven-plugin, maven, spring
Solution
I faced the same problem while trying to make maven bootstrap a database from a hibernate model (issue described in Generate database schema (Hibernate) on maven test).
I got hbm2ddl working quite well with the following combination of versions: Hibernate (runtime): 4.1.7.Final hibernate3-maven-plugin: 3.6.10.Final, specified plugin version 2.2 hibernate3-maven-plugin's hibernate-validator dependency: 4.2.0.Final
Below the relevant parts of the pom:
Versions:
<properties>
<org.hibernate.version>4.1.7.Final</org.hibernate.version>
<hibernate.maven.plugin.version>3.6.10.Final</hibernate.maven.plugin.version>
</properties>
hibernate3-maven-plugin's definition:
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>hibernate3-maven-plugin</artifactId>
<version>2.2</version>
<configuration>
<components>
<component>
<name>hbm2ddl</name>
<implementation>jpaconfiguration</implementation>
</component>
</components>
<componentProperties>
<outputfilename>schema.ddl</outputfilename>
<create>true</create>
<export>false</export>
<format>true</format>
<drop>false</drop>
<jdk5>true</jdk5>
<propertyfile>target/test-classes/application.properties</propertyfile>
<skip>${skipTests}</skip>
</componentProperties>
</configuration>
<executions>
<execution>
<phase>process-classes</phase>
<goals>
<goal>hbm2ddl</goal>
</goals>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>${hibernate.maven.plugin.version}</version>
<exclusions>
<exclusion>
<groupId>cglib</groupId>
<artifactId>cglib</artifactId>
</exclusion>
<exclusion>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>${hibernate.maven.plugin.version}</version>
<exclusions>
<exclusion>
<groupId>cglib</groupId>
<artifactId>cglib</artifactId>
</exclusion>
<exclusion>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-validator</artifactId>
<version>4.2.0.Final</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
Runtime dependencies:
<dependencies>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>${org.hibernate.version}</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>${org.hibernate.version}</version>
</dependency>
</dependencies>
I hope this helps.
Problem
I had to downgrade Hibernate from version 4 to version 3 (3.3.2.GA to be specific), due to current lack of support for Hibernate 4 within Spring, and now the project fails to build when it attempts to generate schema with hbm2ddl. The error is too vague, and Google-ing it hasn't yielded much. Here's my pom.xml: ``` <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.example</groupId> <artifactId>example</artifactId> <version>1.0-SNAPSHOT</version> <name>Spring + Hibernate Example</name> <packaging>jar</packaging> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <spring.version>3.1.2.RELEASE</spring.version> <hibernate.version>3.3.2.GA</hibernate.version> <java.version>1.6</java.version> </properties> <build> <extensions> <extension> <groupId>org.hsqldb</groupId> <artifactId>hsqldb</artifactId> <version>2.0.0</version> </extension> <extension> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </extension> </extensions> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>2.0.2</version> <configuration> <source>${java.version}</source> <target>${java.version}</target> </configuration> </plugin> <plugin> <!-- Run "mvn hibernate3:hbm2ddl" to generate schema --> <groupId>org.codehaus.mojo</groupId> <artifactId>hibernate3-maven-plugin</artifactId> <version>3.0</version> <executions> <execution> <id>generate-ddl</id> <phase>process-classes</phase> <goals> <goal>hbm2ddl</goal> </goals> </execution> </executions> <configuration> <hibernatetool destdir="${project.build.directory}/generated"> <annotationConfiguration configurationfile="hibernate.cfg.xml"/> <hbm2ddl export="false" create="true" update="true" format="format" outputfilename="schemaDiff.ddl"/> </hibernatetool> </configuration> </plugin> </plugins> </build> <dependencies> <!-- Inversion of Control: Spring Dependencies --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${spring.version}</version> <exclusions> <!-- Exclude the problematic commons-logging --> <exclusion> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>commons-dbcp</groupId> <artifactId>commons-dbcp</artifactId> <version>1.4</version> </dependency> <!-- Object Relational Mapping: Hibernate --> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>${hibernate.version}</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-entitymanager</artifactId> <version>${hibernate.version}</version> </dependency> <dependency> <groupId>javax.transaction</groupId> <artifactId>jta</artifactId> <version>1.1</version> </dependency> <dependency> <groupId>org.hibernate.javax.persistence</groupId> <artifactId>hibernate-jpa-2.0-api</artifactId> <version>1.0.1.Final</version> </dependency> <!-- Hibernate Annotations Dependencies --> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-annotations</artifactId> <version>3.5.6-Final</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-commons-annotations</artifactId> <version>3.3.0.ga</version> </dependency> <!-- Database: HSQLDB --> <dependency> <groupId>org.hsqldb</groupId> <artifactId>hsqldb</artifactId> <version>2.0.0</version> </dependency> <!-- Connection Pool: C3P0 --> <dependency> <groupId>c3p0</groupId> <artifactId>c3p0</artifactId> <version>0.9.1.2</version> </dependency> <!-- Second-level caching: Ehcache --> <dependency> <groupId>ehcache</groupId> <artifactId>ehcache</artifactId> <version>1.2.3</version> </dependency> <!-- Logging: SLF4j & Log4J --> <dependency> <groupId>org.slf4j</groupId> <artifactId>jcl-over-slf4j</artifactId> <version>1.6.6</version> <scope>runtime</scope> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>1.6.6</version> <scope>runtime</scope> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>1.6.6</version> <scope>runtime</scope> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> <scope>runtime</scope> </dependency> <!-- Testing: JUnit --> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.10</version> </dependency> <!-- Testing: Spring --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> </dependency> </dependencies> </project> ``` Running ``` mvn hibernate3:hbm2ddl ``` fails with ``` [ERROR] Failed to execute goal org.codehaus.mojo:hibernate3-maven-plugin:3.0:hbm2ddl (default-cli) on project example: There was an error creating the AntRun task. NullPointerException -> [Help 1] ``` The full stack trace is: ``` [ERROR] Failed to execute goal org.codehaus.mojo:hibernate3-maven-plugin:3.0:hbm2ddl (default-cli) on project example: There was an error creating the AntRun task. NullPointerException -> [Help 1] org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.codehaus.mojo:hibernate3-maven-plugin:3.0:hbm2ddl (default-cli) on project example: There was an error creating the AntRun task. at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:217) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59) at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183) at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161) at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:319) at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156) at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537) at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196) at org.apache.maven.cli.MavenCli.main(MavenCli.java:141) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290) at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230) at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409) at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352) Caused by: org.apache.maven.plugin.MojoExecutionException: There was an error creating the AntRun task. at org.codehaus.mojo.hibernate3.AbstractHibernateMojo.execute(AbstractHibernateMojo.java:84) at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209) ... 19 more Caused by: java.lang.NullPointerException at org.codehaus.plexus.configuration.DefaultPlexusConfiguration.add(DefaultPlexusConfiguration.java:174) at org.codehaus.plexus.configuration.DefaultPlexusConfiguration.addChild(DefaultPlexusConfiguration.java:150) at org.codehaus.mojo.hibernate3.util.PlexusConfigurationUtils.setHibernateConfiguration(PlexusConfigurationUtils.java:289) at org.codehaus.mojo.hibernate3.util.PlexusConfigurationUtils.parseHibernateTool(PlexusConfigurationUtils.java:67) at org.codehaus.mojo.hibernate3.AbstractHibernateToolMojo.getConfiguration(AbstractHibernateToolMojo.java:60) at org.codehaus.mojo.hibernate3.AbstractHibernateMojo.execute(AbstractHibernateMojo.java:76) ... 21 more ``` Hopefully someone can shed some light on this!