Q:

Why does Spark report "java.net.URISyntaxException: Relative path in absolute URI" when working with DataFrames?

I am running Spark locally on a Windows machine. I was able to launch the spark shell successfully and also read in text files as RDDs. I was also able to follow along the various online tutorials on this subject and was able to perform various operations on the RDDs.
However, when I try to convert an RDD into a DataFrame I am getting an error. This is what I am doing:
val sqlContext = new org.apache.spark.sql.SQLContext(sc)
import sqlContext.implicits._

//convert rdd to df
val df = rddFile.toDF()

This code generates a long series of error messages that seem to relate to the following one:
Caused by: java.lang.IllegalArgumentException: java.net.URISyntaxException: Relative path in absolute URI: file:C:/Users/spark/spark-warehouse
        at org.apache.hadoop.fs.Path.initialize(Path.java:205)
        at org.apache.hadoop.fs.Path.<init>(Path.java:171)
        at org.apache.hadoop.hive.metastore.Warehouse.getWhRoot(Warehouse.java:159)
        at org.apache.hadoop.hive.metastore.Warehouse.getDefaultDatabasePath(Warehouse.java:177)
        at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.createDefaultDB_core(HiveMetaStore.java:600)
        at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.createDefaultDB(HiveMetaStore.java:620)
        at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.init(HiveMetaStore.java:461)
        at org.apache.hadoop.hive.metastore.RetryingHMSHandler.<init>(RetryingHMSHandler.java:66)
        at org.apache.hadoop.hive.metastore.RetryingHMSHandler.getProxy(RetryingHMSHandler.java:72)
        at org.apache.hadoop.hive.metastore.HiveMetaStore.newRetryingHMSHandler(HiveMetaStore.java:5762)
        at org.apache.hadoop.hive.metastore.HiveMetaStoreClient.<init>(HiveMetaStoreClient.java:199)
        at org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient.<init>(SessionHiveMetaStoreClient.java:74)
        ... 85 more
Caused by: java.net.URISyntaxException: Relative path in absolute URI: file:C:/Users/spark/spark-warehouse
        at java.net.URI.checkPath(URI.java:1823)
        at java.net.URI.<init>(URI.java:745)
        at org.apache.hadoop.fs.Path.initialize(Path.java:202)
        ... 96 more

The entire stack trace follows.
16/08/16 12:36:20 WARN ObjectStore: Failed to get database default, returning NoSuchObjectException
16/08/16 12:36:20 WARN Hive: Failed to access metastore. This class should not accessed in runtime.
org.apache.hadoop.hive.ql.metadata.HiveException: java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient
        at org.apache.hadoop.hive.ql.metadata.Hive.getAllDatabases(Hive.java:1236)
        at org.apache.hadoop.hive.ql.metadata.Hive.reloadFunctions(Hive.java:174)
        at org.apache.hadoop.hive.ql.metadata.Hive.<clinit>(Hive.java:166)
        at org.apache.hadoop.hive.ql.session.SessionState.start(SessionState.java:503)
        at org.apache.spark.sql.hive.client.HiveClientImpl.<init>(HiveClientImpl.scala:171)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at org.apache.spark.sql.hive.client.IsolatedClientLoader.createClient(IsolatedClientLoader.scala:258)
        at org.apache.spark.sql.hive.HiveUtils$.newClientForMetadata(HiveUtils.scala:359)
        at org.apache.spark.sql.hive.HiveUtils$.newClientForMetadata(HiveUtils.scala:263)
        at org.apache.spark.sql.hive.HiveSharedState.metadataHive$lzycompute(HiveSharedState.scala:39)
        at org.apache.spark.sql.hive.HiveSharedState.metadataHive(HiveSharedState.scala:38)
        at org.apache.spark.sql.hive.HiveSharedState.externalCatalog$lzycompute(HiveSharedState.scala:46)
        at org.apache.spark.sql.hive.HiveSharedState.externalCatalog(HiveSharedState.scala:45)
        at org.apache.spark.sql.hive.HiveSessionState.catalog$lzycompute(HiveSessionState.scala:50)
        at org.apache.spark.sql.hive.HiveSessionState.catalog(HiveSessionState.scala:48)
        at org.apache.spark.sql.hive.HiveSessionState$$anon$1.<init>(HiveSessionState.scala:63)
        at org.apache.spark.sql.hive.HiveSessionState.analyzer$lzycompute(HiveSessionState.scala:63)
        at org.apache.spark.sql.hive.HiveSessionState.analyzer(HiveSessionState.scala:62)
        at org.apache.spark.sql.execution.QueryExecution.assertAnalyzed(QueryExecution.scala:49)
        at org.apache.spark.sql.Dataset$.ofRows(Dataset.scala:64)
        at org.apache.spark.sql.SparkSession.baseRelationToDataFrame(SparkSession.scala:382)
        at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:143)
        at org.apache.spark.sql.DataFrameReader.csv(DataFrameReader.scala:401)
        at org.apache.spark.sql.DataFrameReader.csv(DataFrameReader.scala:342)
        at $line14.$read$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw.<init>(<console>:24)
        at $line14.$read$$iw$$iw$$iw$$iw$$iw$$iw$$iw.<init>(<console>:29)
        at $line14.$read$$iw$$iw$$iw$$iw$$iw$$iw.<init>(<console>:31)
        at $line14.$read$$iw$$iw$$iw$$iw$$iw.<init>(<console>:33)
        at $line14.$read$$iw$$iw$$iw$$iw.<init>(<console>:35)
        at $line14.$read$$iw$$iw$$iw.<init>(<console>:37)
        at $line14.$read$$iw$$iw.<init>(<console>:39)
        at $line14.$read$$iw.<init>(<console>:41)
        at $line14.$read.<init>(<console>:43)
        at $line14.$read$.<init>(<console>:47)
        at $line14.$read$.<clinit>(<console>)
        at $line14.$eval$.$print$lzycompute(<console>:7)
        at $line14.$eval$.$print(<console>:6)
        at $line14.$eval.$print(<console>)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at scala.tools.nsc.interpreter.IMain$ReadEvalPrint.call(IMain.scala:786)
        at scala.tools.nsc.interpreter.IMain$Request.loadAndRun(IMain.scala:1047)
        at scala.tools.nsc.interpreter.IMain$WrappedRequest$$anonfun$loadAndRunReq$1.apply(IMain.scala:638)
        at scala.tools.nsc.interpreter.IMain$WrappedRequest$$anonfun$loadAndRunReq$1.apply(IMain.scala:637)
        at scala.reflect.internal.util.ScalaClassLoader$class.asContext(ScalaClassLoader.scala:31)
        at scala.reflect.internal.util.AbstractFileClassLoader.asContext(AbstractFileClassLoader.scala:19)
        at scala.tools.nsc.interpreter.IMain$WrappedRequest.loadAndRunReq(IMain.scala:637)
        at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:569)
        at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:565)
        at scala.tools.nsc.interpreter.ILoop.interpretStartingWith(ILoop.scala:807)
        at scala.tools.nsc.interpreter.ILoop.command(ILoop.scala:681)
        at scala.tools.nsc.interpreter.ILoop.processLine(ILoop.scala:395)
        at scala.tools.nsc.interpreter.ILoop.loop(ILoop.scala:415)
        at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply$mcZ$sp(ILoop.scala:923)
        at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply(ILoop.scala:909)
        at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply(ILoop.scala:909)
        at scala.reflect.internal.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:97)
        at scala.tools.nsc.interpreter.ILoop.process(ILoop.scala:909)
        at org.apache.spark.repl.Main$.doMain(Main.scala:68)
        at org.apache.spark.repl.Main$.main(Main.scala:51)
        at org.apache.spark.repl.Main.main(Main.scala)
        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.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:729)
        at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:185)
        at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:210)
        at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:124)
        at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
Caused by: java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient
        at org.apache.hadoop.hive.metastore.MetaStoreUtils.newInstance(MetaStoreUtils.java:1523)
        at org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.<init>(RetryingMetaStoreClient.java:86)
        at org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.getProxy(RetryingMetaStoreClient.java:132)
        at org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.getProxy(RetryingMetaStoreClient.java:104)
        at org.apache.hadoop.hive.ql.metadata.Hive.createMetaStoreClient(Hive.java:3005)
        at org.apache.hadoop.hive.ql.metadata.Hive.getMSC(Hive.java:3024)
        at org.apache.hadoop.hive.ql.metadata.Hive.getAllDatabases(Hive.java:1234)
        ... 74 more
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at org.apache.hadoop.hive.metastore.MetaStoreUtils.newInstance(MetaStoreUtils.java:1521)
        ... 80 more
Caused by: java.lang.IllegalArgumentException: java.net.URISyntaxException: Relative path in absolute URI: file:C:/Users/spark/spark-warehouse
        at org.apache.hadoop.fs.Path.initialize(Path.java:205)
        at org.apache.hadoop.fs.Path.<init>(Path.java:171)
        at org.apache.hadoop.hive.metastore.Warehouse.getWhRoot(Warehouse.java:159)
        at org.apache.hadoop.hive.metastore.Warehouse.getDefaultDatabasePath(Warehouse.java:177)
        at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.createDefaultDB_core(HiveMetaStore.java:600)
        at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.createDefaultDB(HiveMetaStore.java:620)
        at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.init(HiveMetaStore.java:461)
        at org.apache.hadoop.hive.metastore.RetryingHMSHandler.<init>(RetryingHMSHandler.java:66)
        at org.apache.hadoop.hive.metastore.RetryingHMSHandler.getProxy(RetryingHMSHandler.java:72)
        at org.apache.hadoop.hive.metastore.HiveMetaStore.newRetryingHMSHandler(HiveMetaStore.java:5762)
        at org.apache.hadoop.hive.metastore.HiveMetaStoreClient.<init>(HiveMetaStoreClient.java:199)
        at org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient.<init>(SessionHiveMetaStoreClient.java:74)
        ... 85 more
Caused by: java.net.URISyntaxException: Relative path in absolute URI: file:C:/Users/spark/spark-warehouse
        at java.net.URI.checkPath(URI.java:1823)
        at java.net.URI.<init>(URI.java:745)
        at org.apache.hadoop.fs.Path.initialize(Path.java:202)
        ... 96 more

A:

It's the SPARK-15565 issue in Spark 2.0 on Windows with a simple solution (that appears to be part of Spark's codebase that may soon be released as 2.0.2 or 2.1.0).
The solution in Spark 2.0.0 is to set spark.sql.warehouse.dir to some properly-referenced directory, say file:///c:/Spark/spark-2.0.0-bin-hadoop2.7/spark-warehouse that uses /// (triple slashes).
Start spark-shell with --conf argument as follows:
spark-shell --conf spark.sql.warehouse.dir=file:///c:/tmp/spark-warehouse

Or create a SparkSession in your Spark application using the new fluent builder pattern as follows:
import org.apache.spark.sql.SparkSession
SparkSession spark = SparkSession
  .builder()
  .config("spark.sql.warehouse.dir", "file:///c:/tmp/spark-warehouse")
  .getOrCreate()

Or create conf/spark-defaults.conf with the following content:
spark.sql.warehouse.dir file:///c:/tmp/spark-warehouse

A:

If you do want to fix it in code yet not touch exsiting code, can also pass it from system properties, such that the spark initializations which comes after won't change.
System.setProperty(
    "spark.sql.warehouse.dir", 
    s"file:///${System.getProperty("user.dir")}/spark-warehouse"
    .replaceAll("\\\\", "/")
)

Note, also this is using the current working dir, which can be replaced with "c:/tmp/", or any place you'd like the spark-warehouse dir.

