Hibernateの “C3P0″接続プールエラーです。これはC3P0の依存関係ライブラリがないために発生します。

Initial SessionFactory creation failed.java.lang.NoClassDefFoundError: com/mchange/v2/c3p0/DataSources
Exception in thread "main" java.lang.ExceptionInInitializerError
    at com.mkyong.persistence.HibernateUtil.buildSessionFactory(HibernateUtil.java:19)
    at com.mkyong.persistence.HibernateUtil.<clinit>(HibernateUtil.java:8)
    at com.mkyong.common.App.main(App.java:11)
Caused by: java.lang.NoClassDefFoundError: com/mchange/v2/c3p0/DataSources
    at org.hibernate.connection.C3P0ConnectionProvider.configure(C3P0ConnectionProvider.java:154)
    at org.hibernate.connection.ConnectionProviderFactory.newConnectionProvider(ConnectionProviderFactory.java:124)
    at org.hibernate.connection.ConnectionProviderFactory.newConnectionProvider(ConnectionProviderFactory.java:56)
    at org.hibernate.cfg.SettingsFactory.createConnectionProvider(SettingsFactory.java:410)
    at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:62)
    at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2009)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1292)
    at com.mkyong.persistence.HibernateUtil.buildSessionFactory(HibernateUtil.java:13)
    ... 2 more
Caused by: java.lang.ClassNotFoundException: com.mchange.v2.c3p0.DataSources
    at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
    ... 10 more

解決策

ライブラリはhttp://www.mchange.com/projects/c3p0/からダウンロードできます。

または

Mavenの座標を使う

        <dependency>
        <groupId>c3p0</groupId>
        <artifactId>c3p0</artifactId>
        <version>0.9.1.2</version>
    </dependency>