NPE when unable to init the driver

[arina-ielchiieva]

Command:
/usr/lib/jvm/java-1.8.0-openjdk/bin/java -cp ... sqlline.SqlLine -d org.apache.drill.jdbc.Dri --maxWidth=10000

org.apache.drill.jdbc.Dri
java.lang.NullPointerException
sqlline version 1.5.0-SNAPSHOT
0: jdbc:drill:zk=local> !quit
java.lang.ClassNotFoundException: org.apache.drill.jdbc.Dri
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:264)
	at sqlline.DatabaseConnection.connect(DatabaseConnection.java:114)
	at sqlline.DatabaseConnection.getConnection(DatabaseConnection.java:204)
	at sqlline.Commands.close(Commands.java:920)
	at sqlline.Commands.quit(Commands.java:877)
	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 sqlline.ReflectiveCommandHandler.execute(ReflectiveCommandHandler.java:38)
	at sqlline.SqlLine.dispatch(SqlLine.java:806)
	at sqlline.SqlLine.begin(SqlLine.java:683)
	at sqlline.SqlLine.start(SqlLine.java:374)
	at sqlline.SqlLine.main(SqlLine.java:266)
Connection is already closed.

Sqlline displays the incorrect driver class name with NPE afterwards. Does not fail and only after issuing quit command, displays full error message.
Actually, not quite sure why sqlline does not fail completely if passed driver is incorrect.

[snuyanzin]

Was not able to reproduce NPE
However was able to reproduce issue related to fail in exit. It also appears right after !connect command which I do not see in your example. How do you initialize connect?
The reason is that on !quit close method tries to close connections getting from getConnection. At the same time getConnection returns existing or initiates a new one if there is no existing and that is strange if we are talking about close method. So I have such a trace twice: first after !connect, second after !close

[arina-ielchiieva]

@snuyanzin what errors do you get when you pass incorrect driver name (ex: -d incorrect_name)? Because I see the NPE on the latest master as well. It occurs when setComplections are called (https://github.com/julianhyde/sqlline/blob/master/src/main/java/sqlline/Commands.java#L1110).

[snuyanzin]

Yes, sorry, my fault
the test to reproduce NPE
sqlline.SqlLineArgsTest

@Test
public void testTablesH2WithErrorDriver() throws Throwable {
    connectionSpec = ConnectionSpec.ERROR_H2_DRIVER;
    final String script = "!tables\n";

    checkScriptFile(script, true, equalTo(SqlLine.Status.OK),
        not(containsString("NullPointerException")));
}
...
public static final ConnectionSpec ERROR_H2_DRIVER =
        new ConnectionSpec("jdbc:h2:mem:", "sa", "", "ERROR_DRIVER");

[julianhyde]

Fixed in 9b0f7b8.

[arina-ielchiieva]

Verified:

Could not find driver org.apache.drill.jdbc.Dri; using registered driver org.apache.drill.jdbc.Driver instead
Aug 26, 2018 2:07:51 PM org.glassfish.jersey.server.ApplicationHandler initialize
INFO: Initiating Jersey application, version Jersey: 2.8 2014-04-29 01:25:26...
sqlline version 1.5.0-SNAPSHOT
0: jdbc:drill:zk=local> !quit
Closing: org.apache.drill.jdbc.impl.DrillConnectionImpl