[LOG4J2-1532] Don't throw an NPE from org.apache.logging.log4j.core.LoggerContext.setConfiguration(Configuration) when the configuration is missing

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.6, 2.6.1, 2.6.2
• Fix Version/s: 2.7
• Component/s: Configurators
• Assignee: Gary D. Gregory
• Reporter: Gary D. Gregory
• Created: 18/Aug/16 22:28
• Updated: 23/Aug/16 00:39
• Resolved: 23/Aug/16 00:17

Description

Don't throw an NPE from org.apache.logging.log4j.core.LoggerContext.setConfiguration(Configuration) when the configuration is missing.

I am seeing this in a customer use case with what the customer says is version "2.6.x."

The method org.apache.logging.log4j.core.LoggerContext.setConfiguration(Configuration) throws an exception when the given Configuration is null.

This can happen when the method is called by org.apache.logging.log4j.core.LoggerContext.reconfigure(URI) and the file backing the URI has disappeared.

Thoughts?

I propose that we either:

1. Log an ERROR from org.apache.logging.log4j.core.LoggerContext.setConfiguration(Configuration) instead of throwing an NPE; or
2. Change the implementation of org.apache.logging.log4j.core.LoggerContext.reconfigure(URI) to check for a null answer from ConfigurationFactory.getInstance().getConfiguration(contextName, configURI, cl); and log an ERROR if null.
3. Do both (the best IMO.)

The exception I've see is (I had to change some class names and package names):

> Name: java.lang.NullPointerException
> Message: No Configuration was provided
> StackTrace: java.util.Objects.requireNonNull(Objects.java:228)
> org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:477)
> org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:561)
> org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:577)
> org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:212)
> org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:152)
> org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45)
> org.apache.logging.log4j.LogManager.getContext(LogManager.java:194)
> com.example.log.MyLoggerHelperFactory.getLoggerContext(MyLoggerHelperFactory.java:79)
> com.example.log.MyLoggerHelperFactory.getFormatterLogger(MyLoggerHelperFactory.java:73)
> com.example.log.MyLoggerHelperFactory.getFormatterLogger(MyLoggerHelperFactory.java:68)
> com.example.MyLoggerHelper.<init>(MyLoggerHelper.java:67)
> com.example.MyLoggerHelper.<init>(MyLoggerHelper.java:57)
> com.example.MyAbstractObject.<init>(MyAbstractObject.java:27)
> com.example.MyMain.<init>(MyMain.java:125)
> com.example.MyMain.<clinit>(MyMain.java:24)
> sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
> sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
> sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
> sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
> sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
> java.lang.reflect.Constructor.newInstance(Constructor.java:408)
> java.lang.Class.newInstance(Class.java:433)
> org.apache.spark.sql.execution.datasources.jdbc.DriverRegistry$.register(DriverRegistry.scala:46)
> org.apache.spark.sql.execution.datasources.jdbc.DefaultSource.createRelation(DefaultSource.scala:41)
> org.apache.spark.sql.execution.datasources.ResolvedDataSource$.apply(ResolvedDataSource.scala:125)
> org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:114)
> $line86.$read$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:49)
> $line86.$read$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:54)
> $line86.$read$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:56)
> $line86.$read$$iwC$$iwC$$iwC$$iwC.<init>(<console>:58)
> $line86.$read$$iwC$$iwC$$iwC.<init>(<console>:60)
> $line86.$read$$iwC$$iwC.<init>(<console>:62)
> $line86.$read$$iwC.<init>(<console>:64)
> $line86.$read.<init>(<console>:66)
> $line86.$read$.<init>(<console>:70)
> $line86.$read$.<clinit>(<console>)
> $line86.$eval$.<init>(<console>:7)
> $line86.$eval$.<clinit>(<console>)
> $line86.$eval.$print(<console>)
> sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> java.lang.reflect.Method.invoke(Method.java:483)
> org.apache.spark.repl.SparkIMain$ReadEvalPrint.call(SparkIMain.scala:1065)
> org.apache.spark.repl.SparkIMain$Request.loadAndRun(SparkIMain.scala:1340)
> org.apache.spark.repl.SparkIMain.loadAndRunReq$1(SparkIMain.scala:840)
> org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:871)
> org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:819)
> org.apache.toree.kernel.interpreter.scala.ScalaInterpreter$$anonfun$interpretAddTask$1$$anonfun$apply$3.apply(ScalaInterpreter.scala:361)
> org.apache.toree.kernel.interpreter.scala.ScalaInterpreter$$anonfun$interpretAddTask$1$$anonfun$apply$3.apply(ScalaInterpreter.scala:356)
> org.apache.toree.global.StreamState$.withStreams(StreamState.scala:81)
> org.apache.toree.kernel.interpreter.scala.ScalaInterpreter$$anonfun$interpretAddTask$1.apply(ScalaInterpreter.scala:355)
> org.apache.toree.kernel.interpreter.scala.ScalaInterpreter$$anonfun$interpretAddTask$1.apply(ScalaInterpreter.scala:355)
> org.apache.toree.utils.TaskManager$$anonfun$add$2$$anon$1.run(TaskManager.scala:140)
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> java.lang.Thread.run(Thread.java:745)