在Maven项目中尝试使用OpenJPA连接到Derby数据库，但得到一个；“java.sql.SQLException”；错误。

所以我做了

sudo apt安装sunjavadb客户端sunjavadb-core

。将

javadb/bin

添加到

PATH

并导出

DERBY_HOME

。然后我通过执行

CONNECT'jdbc:derby:/home/ijk/MyDbTest创建了数据库；create=true'使用
ij
。因此
dblook
给出

ijk@ubuntuvm:~$ dblook -d 'jdbc:derby:/home/ijk/MyDbTest'
-- Timestamp: 2014-06-27 18:32:11.933
-- Source database is: /home/ijk/MyDbTest
-- Connection URL is: jdbc:derby:/home/ijk/MyDbTest
-- appendLogs: false

现在我有了一个Maven项目，其中包含以下pom.xml

<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.groupdo</groupId>
<artifactId>server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>server</name>
<url>http://maven.apache.org</url>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>3.8.1</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>org.apache.openjpa</groupId>
        <artifactId>openjpa-all</artifactId>
        <version>2.3.0</version>
    </dependency>

    <dependency>
        <groupId>org.apache.derby</groupId>
        <artifactId>derbyclient</artifactId>
        <version>10.10.2.0</version>
    </dependency>

</dependencies>

以下是
persistence.xml

<?xml version="1.0"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="2.0">
    <persistence-unit name="testjpa" transaction-type="RESOURCE_LOCAL">
        <provider>
            org.apache.openjpa.persistence.PersistenceProviderImpl
        </provider>
        <class>entity.User</class>
        <properties>
            <property name="openjpa.ConnectionURL" value="jdbc:derby:/home/ijk/MyDbTest;create=true" />
            <property name="openjpa.ConnectionDriverName" value="org.apache.derby.jdbc.ClientDriver" />
            <property name="openjpa.ConnectionUserName" value="admin" />
            <property name="openjpa.ConnectionPassword" value="admin" />
            <property name="openjpa.Log" value="SQL=TRACE" />
        </properties>
    </persistence-unit>
</persistence>

我得到以下堆栈跟踪，不知道出了什么问题：

503  testjpa  INFO   [main] openjpa.Runtime - OpenJPA dynamically loaded the class enhancer. Any classes that were not enhanced at build time will be enhanced when they are loaded by the JVM.
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
659  testjpa  INFO   [main] openjpa.Runtime - OpenJPA dynamically loaded a validation provider.
686  testjpa  INFO   [main] openjpa.Runtime - Starting OpenJPA 2.3.0
722  testjpa  INFO   [main] openjpa.jdbc.JDBC - Using dictionary class "org.apache.openjpa.jdbc.sql.DerbyDictionary".
Exception in thread "main" <openjpa-2.3.0-r422266:1540826 nonfatal general error> org.apache.openjpa.persistence.PersistenceException: There were errors initializing your configuration: <openjpa-2.3.0-r422266:1540826 fatal user error> org.apache.openjpa.util.UserException: A connection could not be obtained for driver class "org.apache.derby.jdbc.ClientDriver" and URL "jdbc:derby:/home/ijk/MyDbTest;create=true".  You may have specified an invalid URL.
    at org.apache.openjpa.jdbc.schema.DataSourceFactory.newConnectException(DataSourceFactory.java:255)
    at org.apache.openjpa.jdbc.schema.DataSourceFactory.installDBDictionary(DataSourceFactory.java:241)
    at org.apache.openjpa.jdbc.conf.JDBCConfigurationImpl.getConnectionFactory(JDBCConfigurationImpl.java:733)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.openjpa.lib.conf.ConfigurationImpl.instantiateAll(ConfigurationImpl.java:310)
    at org.apache.openjpa.conf.OpenJPAConfigurationImpl.instantiateAll(OpenJPAConfigurationImpl.java:1670)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.makeReadOnly(AbstractBrokerFactory.java:651)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker(AbstractBrokerFactory.java:203)
    at org.apache.openjpa.kernel.DelegatingBrokerFactory.newBroker(DelegatingBrokerFactory.java:155)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:226)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:153)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:59)
    at com.groupdo.server.Test.main(Test.java:14)
Caused by: org.apache.commons.dbcp.SQLNestedException: Cannot create JDBC driver of class 'org.apache.derby.jdbc.ClientDriver' for connect URL 'jdbc:derby:/home/ijk/MyDbTest;create=true'
    at org.apache.commons.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1452)
    at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1371)
    at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
    at org.apache.openjpa.jdbc.schema.DBCPDriverDataSource.getDBCPConnection(DBCPDriverDataSource.java:74)
    at org.apache.openjpa.jdbc.schema.AutoDriverDataSource.getConnection(AutoDriverDataSource.java:42)
    at org.apache.openjpa.jdbc.schema.SimpleDriverDataSource.getConnection(SimpleDriverDataSource.java:76)
    at org.apache.openjpa.lib.jdbc.DelegatingDataSource.getConnection(DelegatingDataSource.java:118)
    at org.apache.openjpa.lib.jdbc.DecoratingDataSource.getConnection(DecoratingDataSource.java:93)
    at org.apache.openjpa.jdbc.schema.DataSourceFactory.installDBDictionary(DataSourceFactory.java:233)
    ... 14 more
Caused by: java.sql.SQLException: No suitable driver
    at java.sql.DriverManager.getDriver(DriverManager.java:278)
    at org.apache.commons.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1437)
    ... 22 more

    at org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker(AbstractBrokerFactory.java:218)
    at org.apache.openjpa.kernel.DelegatingBrokerFactory.newBroker(DelegatingBrokerFactory.java:155)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:226)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:153)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:59)
    at com.groupdo.server.Test.main(Test.java:14)
Caused by: java.lang.RuntimeException: There were errors initializing your configuration: <openjpa-2.3.0-r422266:1540826 fatal user error> org.apache.openjpa.util.UserException: A connection could not be obtained for driver class "org.apache.derby.jdbc.ClientDriver" and URL "jdbc:derby:/home/ijk/MyDbTest;create=true".  You may have specified an invalid URL.
    at org.apache.openjpa.jdbc.schema.DataSourceFactory.newConnectException(DataSourceFactory.java:255)
    at org.apache.openjpa.jdbc.schema.DataSourceFactory.installDBDictionary(DataSourceFactory.java:241)
    at org.apache.openjpa.jdbc.conf.JDBCConfigurationImpl.getConnectionFactory(JDBCConfigurationImpl.java:733)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.openjpa.lib.conf.ConfigurationImpl.instantiateAll(ConfigurationImpl.java:310)
    at org.apache.openjpa.conf.OpenJPAConfigurationImpl.instantiateAll(OpenJPAConfigurationImpl.java:1670)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.makeReadOnly(AbstractBrokerFactory.java:651)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker(AbstractBrokerFactory.java:203)
    at org.apache.openjpa.kernel.DelegatingBrokerFactory.newBroker(DelegatingBrokerFactory.java:155)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:226)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:153)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:59)
    at com.groupdo.server.Test.main(Test.java:14)
Caused by: org.apache.commons.dbcp.SQLNestedException: Cannot create JDBC driver of class 'org.apache.derby.jdbc.ClientDriver' for connect URL 'jdbc:derby:/home/ijk/MyDbTest;create=true'
    at org.apache.commons.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1452)
    at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1371)
    at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
    at org.apache.openjpa.jdbc.schema.DBCPDriverDataSource.getDBCPConnection(DBCPDriverDataSource.java:74)
    at org.apache.openjpa.jdbc.schema.AutoDriverDataSource.getConnection(AutoDriverDataSource.java:42)
    at org.apache.openjpa.jdbc.schema.SimpleDriverDataSource.getConnection(SimpleDriverDataSource.java:76)
    at org.apache.openjpa.lib.jdbc.DelegatingDataSource.getConnection(DelegatingDataSource.java:118)
    at org.apache.openjpa.lib.jdbc.DecoratingDataSource.getConnection(DecoratingDataSource.java:93)
    at org.apache.openjpa.jdbc.schema.DataSourceFactory.installDBDictionary(DataSourceFactory.java:233)
    ... 14 more
Caused by: java.sql.SQLException: No suitable driver
    at java.sql.DriverManager.getDriver(DriverManager.java:278)
    at org.apache.commons.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1437)
    ... 22 more

    at org.apache.openjpa.lib.conf.ConfigurationImpl.instantiateAll(ConfigurationImpl.java:324)
    at org.apache.openjpa.conf.OpenJPAConfigurationImpl.instantiateAll(OpenJPAConfigurationImpl.java:1670)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.makeReadOnly(AbstractBrokerFactory.java:651)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker(AbstractBrokerFactory.java:203)
    ... 5 more

503 testjpa INFO[main]openjpa.Runtime-openjpa动态加载类增强器。任何在构建时未增强的类在JVM加载时都将得到增强。
SLF4J:未能加载类“org.SLF4J.impl.StaticLoggerBinder”。
SLF4J:默认为无操作（NOP）记录器实现
SLF4J：参见http://www.slf4j.org/codes.html#StaticLoggerBinder 详情请参阅。
659 testjpa INFO[main]openjpa.Runtime-openjpa动态加载验证提供程序。
686 testjpa INFO[main]openjpa.Runtime-启动openjpa 2.3.0
722 testjpa INFO[main]openjpa.jdbc.jdbc-使用字典类“org.apache.openjpa.jdbc.sql.DerbyDictionary”。
线程“main”org.apache.openjpa.persistence.PersistenceException中出现异常：初始化配置时出错：org.apache.openjpa.util.UserException:无法获取驱动程序类“org.apache.derby.jdbc.ClientDriver”和URL“jdbc:derby:/home/ijk/MyDbTest；create=true”的连接。您可能指定了无效的URL。
位于org.apache.openjpa.jdbc.schema.DataSourceFactory.newConnectException（DataSourceFactory.java:255）
位于org.apache.openjpa.jdbc.schema.DataSourceFactory.installDBDictionary（DataSourceFactory.java:241）
位于org.apache.openjpa.jdbc.conf.jdbcconfigurationmpl.getConnectionFactory（jdbcconfigurationmpl.java:733）
在sun.reflect.NativeMethodAccessorImpl.invoke0（本机方法）处
在sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:57）中
在sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）中
位于java.lang.reflect.Method.invoke（Method.java:606）
在org.apache.openjpa.lib.conf.configurationmpl.instanceAll（configurationmpl.java:310）上
位于org.apache.openjpa.conf.OpenJPAConfigurationImpl.instanceAll（OpenJPAConfigurationImpl.java:1670）
位于org.apache.openjpa.kernel.AbstractBrokerFactory.makeReadOnly（AbstractBrokerFactory.java:651）
位于org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker（AbstractBrokerFactory.java:203）
位于org.apache.openjpa.kernel.DelegatingBrokerFactory.newBroker（DelegatingBrokerFactory.java:155）
位于org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager（EntityManagerFactoryImpl.java:226）
位于org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager（EntityManagerFactoryImpl.java:153）
位于org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager（EntityManagerFactoryImpl.java:59）
位于com.groupdo.server.Test.main（Test.java:14）
原因：org.apache.commons.dbcp.SQLNestedException:无法为连接URL“JDBC:derby:/home/ijk/MyDbTest”创建类为“org.apache.derby.JDBC.ClientDriver”的JDBC驱动程序；create=true'
位于org.apache.commons.dbcp.BasicDataSource.createConnectionFactory（BasicDataSource.java:1452）
位于org.apache.commons.dbcp.BasicDataSource.createDataSource（BasicDataSource.java:1371）
位于org.apache.commons.dbcp.BasicDataSource.getConnection（BasicDataSource.java:1044）
位于org.apache.openjpa.jdbc.schema.DBCPDriverDataSource.getDBCPConnection（DBCPDriverDataSource.java:74）
位于org.apache.openjpa.jdbc.schema.AutoDriverDataSource.getConnection（AutoDriverDataSource.java:42）
位于org.apache.openjpa.jdbc.schema.SimpleDriverDataSource.getConnection（SimpleDriverDataSource.java:76）
位于org.apache.openjpa.lib.jdbc.DelegatingDataSource.getConnection（DelegatingDataSource.java:118）
位于org.apache.openjpa.lib.jdbc.DecoratingDataSource.getConnection（DecoratingDataSource.java:93）
位于org.apache.openjpa.jdbc.schema.DataSourceFactory.installDBDictionary（DataSourceFactory.java:233）
... 14多
原因：java.sql.SQLException:没有合适的驱动程序
位于java.sql.DriverManager.getDriver（DriverManager.java:278）
位于org.apache.commons.dbcp.BasicDataSource.createConnectionFactory（BasicDataSource.java:1437）
... 还有22个
位于org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker（AbstractBrokerFactory.java:218）
位于org.apache.openjpa.kernel.DelegatingBrokerFactory.newBroker（DelegatingBrokerFactory.java:155）
位于org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager（EntityManagerFactoryImpl.java:226）
位于org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager（EntityManagerFactoryImpl.java:153）
位于org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager（EntityManagerFactoryImpl.java:59）
位于com.groupdo.server.Test.main（Test.java:14）
原因：java.lang.RuntimeException:初始化配置时出错：org.apache.openjpa.util.UserException:无法获取驱动程序类“org.apache.derby.jdbc.ClientDriver”和URL“jdbc:derby:/home/ijk/MyDbTest；create=true”的连接。您可能指定了无效的URL。
位于org.apache.openjpa.jdbc.schema.DataSourceFactory.newConnectException（DataSourceFactory.java:255）
位于org.apache.openjpa.jdbc.schema.DataSourceFactory.installDBDictionary（DataSourceFactory.java:241）
位于org.apache.openjpa.jdbc.conf.jdbcconfigurationmpl.getConnectionFactory（jdbcconfigurationmpl.java:733）
在sun.reflect.NativeMethodAccessorImpl.invoke0（本机方法）处
在sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:57）中
在sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAc
package com.groupdo.server;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;

import com.groupdo.models.User;

public class Test {

    public static void main(String[] args) {    
        EntityManagerFactory entityManagerFactory =  Persistence.createEntityManagerFactory("testjpa");
        EntityManager em = entityManagerFactory.createEntityManager();
        EntityTransaction userTransaction = em.getTransaction();

        userTransaction.begin();
        User user = new User();
        user.setUsername("alex");
        user.setPassword("pass");
        em.persist(user);
        userTransaction.commit();
        em.close();
        entityManagerFactory.close();
    }

}

503  testjpa  INFO   [main] openjpa.Runtime - OpenJPA dynamically loaded the class enhancer. Any classes that were not enhanced at build time will be enhanced when they are loaded by the JVM.
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
659  testjpa  INFO   [main] openjpa.Runtime - OpenJPA dynamically loaded a validation provider.
686  testjpa  INFO   [main] openjpa.Runtime - Starting OpenJPA 2.3.0
722  testjpa  INFO   [main] openjpa.jdbc.JDBC - Using dictionary class "org.apache.openjpa.jdbc.sql.DerbyDictionary".
Exception in thread "main" <openjpa-2.3.0-r422266:1540826 nonfatal general error> org.apache.openjpa.persistence.PersistenceException: There were errors initializing your configuration: <openjpa-2.3.0-r422266:1540826 fatal user error> org.apache.openjpa.util.UserException: A connection could not be obtained for driver class "org.apache.derby.jdbc.ClientDriver" and URL "jdbc:derby:/home/ijk/MyDbTest;create=true".  You may have specified an invalid URL.
    at org.apache.openjpa.jdbc.schema.DataSourceFactory.newConnectException(DataSourceFactory.java:255)
    at org.apache.openjpa.jdbc.schema.DataSourceFactory.installDBDictionary(DataSourceFactory.java:241)
    at org.apache.openjpa.jdbc.conf.JDBCConfigurationImpl.getConnectionFactory(JDBCConfigurationImpl.java:733)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.openjpa.lib.conf.ConfigurationImpl.instantiateAll(ConfigurationImpl.java:310)
    at org.apache.openjpa.conf.OpenJPAConfigurationImpl.instantiateAll(OpenJPAConfigurationImpl.java:1670)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.makeReadOnly(AbstractBrokerFactory.java:651)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker(AbstractBrokerFactory.java:203)
    at org.apache.openjpa.kernel.DelegatingBrokerFactory.newBroker(DelegatingBrokerFactory.java:155)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:226)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:153)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:59)
    at com.groupdo.server.Test.main(Test.java:14)
Caused by: org.apache.commons.dbcp.SQLNestedException: Cannot create JDBC driver of class 'org.apache.derby.jdbc.ClientDriver' for connect URL 'jdbc:derby:/home/ijk/MyDbTest;create=true'
    at org.apache.commons.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1452)
    at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1371)
    at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
    at org.apache.openjpa.jdbc.schema.DBCPDriverDataSource.getDBCPConnection(DBCPDriverDataSource.java:74)
    at org.apache.openjpa.jdbc.schema.AutoDriverDataSource.getConnection(AutoDriverDataSource.java:42)
    at org.apache.openjpa.jdbc.schema.SimpleDriverDataSource.getConnection(SimpleDriverDataSource.java:76)
    at org.apache.openjpa.lib.jdbc.DelegatingDataSource.getConnection(DelegatingDataSource.java:118)
    at org.apache.openjpa.lib.jdbc.DecoratingDataSource.getConnection(DecoratingDataSource.java:93)
    at org.apache.openjpa.jdbc.schema.DataSourceFactory.installDBDictionary(DataSourceFactory.java:233)
    ... 14 more
Caused by: java.sql.SQLException: No suitable driver
    at java.sql.DriverManager.getDriver(DriverManager.java:278)
    at org.apache.commons.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1437)
    ... 22 more

    at org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker(AbstractBrokerFactory.java:218)
    at org.apache.openjpa.kernel.DelegatingBrokerFactory.newBroker(DelegatingBrokerFactory.java:155)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:226)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:153)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:59)
    at com.groupdo.server.Test.main(Test.java:14)
Caused by: java.lang.RuntimeException: There were errors initializing your configuration: <openjpa-2.3.0-r422266:1540826 fatal user error> org.apache.openjpa.util.UserException: A connection could not be obtained for driver class "org.apache.derby.jdbc.ClientDriver" and URL "jdbc:derby:/home/ijk/MyDbTest;create=true".  You may have specified an invalid URL.
    at org.apache.openjpa.jdbc.schema.DataSourceFactory.newConnectException(DataSourceFactory.java:255)
    at org.apache.openjpa.jdbc.schema.DataSourceFactory.installDBDictionary(DataSourceFactory.java:241)
    at org.apache.openjpa.jdbc.conf.JDBCConfigurationImpl.getConnectionFactory(JDBCConfigurationImpl.java:733)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.openjpa.lib.conf.ConfigurationImpl.instantiateAll(ConfigurationImpl.java:310)
    at org.apache.openjpa.conf.OpenJPAConfigurationImpl.instantiateAll(OpenJPAConfigurationImpl.java:1670)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.makeReadOnly(AbstractBrokerFactory.java:651)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker(AbstractBrokerFactory.java:203)
    at org.apache.openjpa.kernel.DelegatingBrokerFactory.newBroker(DelegatingBrokerFactory.java:155)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:226)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:153)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:59)
    at com.groupdo.server.Test.main(Test.java:14)
Caused by: org.apache.commons.dbcp.SQLNestedException: Cannot create JDBC driver of class 'org.apache.derby.jdbc.ClientDriver' for connect URL 'jdbc:derby:/home/ijk/MyDbTest;create=true'
    at org.apache.commons.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1452)
    at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1371)
    at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
    at org.apache.openjpa.jdbc.schema.DBCPDriverDataSource.getDBCPConnection(DBCPDriverDataSource.java:74)
    at org.apache.openjpa.jdbc.schema.AutoDriverDataSource.getConnection(AutoDriverDataSource.java:42)
    at org.apache.openjpa.jdbc.schema.SimpleDriverDataSource.getConnection(SimpleDriverDataSource.java:76)
    at org.apache.openjpa.lib.jdbc.DelegatingDataSource.getConnection(DelegatingDataSource.java:118)
    at org.apache.openjpa.lib.jdbc.DecoratingDataSource.getConnection(DecoratingDataSource.java:93)
    at org.apache.openjpa.jdbc.schema.DataSourceFactory.installDBDictionary(DataSourceFactory.java:233)
    ... 14 more
Caused by: java.sql.SQLException: No suitable driver
    at java.sql.DriverManager.getDriver(DriverManager.java:278)
    at org.apache.commons.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1437)
    ... 22 more

    at org.apache.openjpa.lib.conf.ConfigurationImpl.instantiateAll(ConfigurationImpl.java:324)
    at org.apache.openjpa.conf.OpenJPAConfigurationImpl.instantiateAll(OpenJPAConfigurationImpl.java:1670)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.makeReadOnly(AbstractBrokerFactory.java:651)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker(AbstractBrokerFactory.java:203)
    ... 5 more