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= Troubleshooting

*  My Spark application or Spark shell hangs when I invoke any action on IgniteRDD

This will happen if you have created `IgniteContext` in client mode (which is default mode) and you do not have any Ignite server nodes started up. In this case Ignite client will wait until server nodes are started or fail after cluster join timeout has elapsed. You should start at least one Ignite server node when using `IgniteContext` in client mode.

*  I am getting `java.lang.ClassNotFoundException` `org.apache.ignite.logger.java.JavaLoggerFileHandler` when using IgniteContext

This issue appears when you do not have any loggers included in classpath and Ignite tries to use standard Java logging. By default Spark loads all user jar files using separate class loader. Java logging framework, on the other hand, uses application class loader to initialize log handlers. To resolve this, you can either add `ignite-log4j` module to the list of the used jars so that Ignite would use Log4j as a logging subsystem, or alter default Spark classpath as described link:ignite-for-spark/installation[here].