[Issue #6967] NoClassDefFoundError when using druid-hdfs-storage

[ankit0811]

Fix:

1. hadoop-common dependency for druid-hdfs and druid-kerberos extensions
   Refactoring:
2. HadoopDruidIndexerConfig.JSON_MAPPER call in the inner static class to avoid class path conflicts for stopGracefully kill

[jon-wei]

There are some real UT failures:

org.apache.druid.segment.loading.HdfsDataSegmentFinderTest  Time elapsed: 2.25 sec  <<< ERROR!
java.lang.NoClassDefFoundError: org/apache/hadoop/net/StaticMapping
	at org.apache.hadoop.hdfs.MiniDFSCluster.initMiniDFSCluster(MiniDFSCluster.java:807)
	at org.apache.hadoop.hdfs.MiniDFSCluster.<init>(MiniDFSCluster.java:485)
	at org.apache.hadoop.hdfs.MiniDFSCluster$Builder.build(MiniDFSCluster.java:444)
	at org.apache.druid.segment.loading.HdfsDataSegmentFinderTest.setupStatic(HdfsDataSegmentFinderTest.java:148)
	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 org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:367)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeWithRerun(JUnit4Provider.java:274)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:238)
	at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:161)
	at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:290)
	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:242)
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:121)
Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.net.StaticMapping
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 21 more

Maybe some adjustment is needed for hadoop-common dependency in test scope

[jon-wei]

@ankit0811 thanks for the fix!