使用SQuirreL连接/咨询分布式MariaDB，每次执行查询后都会得到java.sql.SQLException: java.lang.NullPointerException。它甚至出现在SHOW tables FROM catalog_name;或SHOW columns FROM table_name;类型的查询中。这个驱动程序的常见行为是否有问题？
错误显示在自己的结果中＆＃34;错误＆＃34;选项卡，在选项卡后面，我想要的结果。到目前为止，这只是一个解决它的问题（Ctrl + Shift + F4），所以这是一个小麻烦，因为生成的其他结果选项卡显示了良好的数据。但是我想知道这是否是其他错误的症状（安装，版本协调，......）：看到堆栈跟踪，红色，每次都会在我的脑海里冒出一些旗帜，即使我知道我的结果就在红色文本后面。
我使用Simplicit的vjdbc驱动程序de.simplicit.vjdbc.VirtualDriver.class来连接分布式MariaDB。同一SQuirreL实例中的其他驱动程序（DB2）不显示错误。 vjdbc驱动程序版本是1.6.5。 （自2007年起）并且没有更高版本，并且我无法访问此安装中的明确代码。
JVM是1.7.0_40：
C:\Users\manuelvigarcia>java -version
java version "1.7.0_40"
Java(TM) SE Runtime Environment (build 1.7.0_40-b43)
Java HotSpot(TM) 64-Bit Server VM (build 24.0-b56, mixed mode)
也在SQuirreL＆＃34;中列出＆＃34;：
sun.boot.library.path c:\Program Files (x86)\Java\jdk1.7.0_40\jre\bin
java.vm.version 24.0-b56
和SQuirreL版本是3.6
我认为错误是在Simplicit VirtualDriver中产生的，给定了异常堆栈跟踪的顶部，但我无法访问代码。
最后，我将展示查询：
SELECT latitude, longitude, country_id FROM appartment_master.studio
WHERE appartment_id = 3000;
产生正确的结果窗格：
latitude longitude country_id
12.59565 38.76614 11
带有异常堆栈跟踪的错误窗格：
Error: java.sql.SQLException: java.lang.NullPointerException
at de.simplicit.vjdbc.serial.StreamingResultSet.populate(StreamingResultSet.java:141)
at de.simplicit.vjdbc.server.command.ConnectionEntry.handleResultSet(ConnectionEntry.java:337)
at de.simplicit.vjdbc.server.command.ConnectionEntry.executeCommand(ConnectionEntry.java:223)
at de.simplicit.vjdbc.server.command.CommandProcessor.process(CommandProcessor.java:169)
at de.simplicit.vjdbc.server.rmi.CommandSinkRmiImpl.process(CommandSinkRmiImpl.java:39)
at sun.reflect.GeneratedMethodAccessor81.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:322)
at sun.rmi.transport.Transport$2.run(Transport.java:202)
at sun.rmi.transport.Transport$2.run(Transport.java:199)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:198)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:567)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:828)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.access$400(TCPTransport.java:619)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$1.run(TCPTransport.java:684)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$1.run(TCPTransport.java:681)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:681)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
at de.simplicit.vjdbc.util.SQLExceptionHelper.wrapThrowable(SQLExceptionHelper.java:59)
at de.simplicit.vjdbc.util.SQLExceptionHelper.wrap(SQLExceptionHelper.java:17)
at de.simplicit.vjdbc.server.command.CommandProcessor.process(CommandProcessor.java:180)
at de.simplicit.vjdbc.server.rmi.CommandSinkRmiImpl.process(CommandSinkRmiImpl.java:39)
at sun.reflect.GeneratedMethodAccessor81.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:322)
at sun.rmi.transport.Transport$2.run(Transport.java:202)
at sun.rmi.transport.Transport$2.run(Transport.java:199)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:198)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:567)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:828)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.access$400(TCPTransport.java:619)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$1.run(TCPTransport.java:684)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$1.run(TCPTransport.java:681)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:681)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:275)
at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:252)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:161)
at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:194)
at java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:148)
at com.sun.proxy.$Proxy6.process(Unknown Source)
at de.simplicit.vjdbc.rmi.CommandSinkRmiProxy.process(CommandSinkRmiProxy.java:40)
at de.simplicit.vjdbc.command.DecoratedCommandSink.process(DecoratedCommandSink.java:69)
at de.simplicit.vjdbc.VirtualStatement.getResultSet(VirtualStatement.java:150)
at net.sourceforge.squirrel_sql.client.session.StatementWrapper.getResultSetWrapper(StatementWrapper.java:101)
at net.sourceforge.squirrel_sql.client.session.SQLExecuterTask.processQuery(SQLExecuterTask.java:398)
at net.sourceforge.squirrel_sql.client.session.SQLExecuterTask.run(SQLExecuterTask.java:212)
at net.sourceforge.squirrel_sql.fw.util.TaskExecuter.run(TaskExecuter.java:82)
at java.lang.Thread.run(Thread.java:724)
SQLState: null
ErrorCode: 0