So we can turn style checker on for test code.

Author: Reynold Xin <rxin@databricks.com>

Closes #5411 from rxin/test-style-mllib and squashes the following commits:

d8a2569 [Reynold Xin] [SPARK-6765] Fix test code style for mllib.

So we can turn style checker on for test code.

Author: Reynold Xin <rxin@databricks.com>

Closes #5410 from rxin/test-style-graphx and squashes the following commits:

89e253a [Reynold Xin] [SPARK-6765] Fix test code style for graphx.

Prior to this change, the unit test for SPARK-3426 did not clone the
original SparkConf, which meant that that test did not use the options
set by suites that subclass ShuffleSuite.scala. This commit fixes that
problem.

JoshRosen would be great if you could take a look at this, since you wrote this
test originally.

Author: Kay Ousterhout <kayousterhout@gmail.com>

Closes #5401 from kayousterhout/SPARK-6753 and squashes the following commits:

368c540 [Kay Ousterhout] [SPARK-6753] Clone SparkConf in ShuffleSuite tests

....

In particular, this makes pyspark in yarn-cluster mode fail unless
SPARK_HOME is set, when it's not really needed.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #5405 from vanzin/SPARK-6506 and squashes the following commits:

e184507 [Marcelo Vanzin] [SPARK-6506] [pyspark] Do not try to retrieve SPARK_HOME when not needed.

So we can turn style checker on for test code.

Author: Reynold Xin <rxin@databricks.com>

Closes #5409 from rxin/test-style-streaming and squashes the following commits:

7aea69b [Reynold Xin] [SPARK-6765] Fix test code style for streaming.

The TaskContextHelper was originally necessary because TaskContext was written in Java, which does
not have a way to specify that classes are package-private, so TaskContextHelper existed to work
around this. Now that TaskContext has been re-written in Scala, this class is no longer necessary.

rxin can you look at this? It looks like you missed this bit of cleanup when you moved TaskContext from Java to Scala in #4324

cc ScrapCodes and pwendell who added this originally.

Author: Kay Ousterhout <kayousterhout@gmail.com>

Closes #5402 from kayousterhout/SPARK-6754 and squashes the following commits:

f089800 [Kay Ousterhout] [SPARK-6754] Remove unnecessary TaskContextHelper

I have the fit intercept enabled by default for logistic regression, I
wonder what others think here. I understand that it enables allocation
by default which is undesirable, but one needs to have a very strong
reason for not having an intercept term enabled so it is the safer
default from a statistical sense.

Explicitly modeling the intercept by adding a column of all 1s does not
work. I believe the reason is that since the API for
LogisticRegressionWithLBFGS forces column normalization, and a column of all
1s has 0 variance so dividing by 0 kills it.

Author: Omede Firouz <ofirouz@palantir.com>

Closes #5301 from oefirouz/addIntercept and squashes the following commits:

9f1286b [Omede Firouz] [SPARK-6705][MLLIB] Add fitInterceptTerm to LogisticRegression
1d6bd6f [Omede Firouz] [SPARK-6705][MLLIB] Add a fit intercept term to ML LogisticRegression
9963509 [Omede Firouz] [MLLIB] Add fitIntercept to LogisticRegression
2257fca [Omede Firouz] [MLLIB] Add fitIntercept param to logistic regression
329c1e2 [Omede Firouz] [MLLIB] Add fit intercept term
bd9663c [Omede Firouz] [MLLIB] Add fit intercept api to ml logisticregression

This patch fixes a memory leak in the DAGScheduler, which caused us to leak a map entry per submitted stage.  The problem is that the OutputCommitCoordinator needs to be informed when stages end in order to remove entries from its `authorizedCommitters` map, but the DAGScheduler only called it in one of the four code paths that are used to mark stages as completed.

This patch fixes this issue by consolidating the processing of stage completion into a new `markStageAsFinished` method and updates DAGSchedulerSuite's `assertDataStructuresEmpty` assertion to also check the OutputCommitCoordinator data structures.  I've also added a comment at the top of DAGScheduler so that we remember to update this test when adding new data structures.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #5397 from JoshRosen/SPARK-6737 and squashes the following commits:

af3b02f [Josh Rosen] Consolidate stage completion handling code in a single method.
e96ce3a [Josh Rosen] Consolidate stage completion handling code in a single method.
3052aea [Josh Rosen] Comment update
7896899 [Josh Rosen] Fix SPARK-6737 by informing OutputCommitCoordinator of all stage end events.
4ead1dc [Josh Rosen] Add regression tests for SPARK-6737

`DataFrame.collect()` calls `SparkPlan.executeCollect()`, which consists of a single line:

```scala
execute().map(ScalaReflection.convertRowToScala(_, schema)).collect()
```

The problem is that, `QueryPlan.schema` is a function. And since 1.3.0, `convertRowToScala` starts returning a `GenericRowWithSchema`. Thus, every `GenericRowWithSchema` instance holds a separate copy of the schema object. Also, YJP profiling result of the following simple micro benchmark (executed in Spark shell) shows that constructing the schema object takes up to ~35% CPU time.

```scala
sc.parallelize(1 to 10000000).
  map(i => (i, s"val_$i")).
  toDF("key", "value").
  saveAsParquetFile("file:///tmp/src.parquet")

// Profiling started from this line
sqlContext.parquetFile("file:///tmp/src.parquet").collect()
```

<!-- Reviewable:start -->
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Author: Cheng Lian <lian@databricks.com>

Closes #5398 from liancheng/spark-6748 and squashes the following commits:

3159469 [Cheng Lian] Makes QueryPlan.schema a lazy val

... and normL2.
Add test cases to insufficient unit test for `normL1` and `normL2`.

Ref: https://github.com/apache/spark/pull/5359

Author: lewuathe <lewuathe@me.com>

Closes #5374 from Lewuathe/SPARK-6720 and squashes the following commits:

5541b24 [lewuathe] More accurate tests
dc5718c [lewuathe] [SPARK-6720] PySpark MultivariateStatisticalSummary unit test for normL1 and normL2

Revert "[SPARK-6568] spark-shell.cmd --jars option does not accept the jar that has space in its path"

This reverts commit 596ba77c.

escape spaces in the arguments.

Author: Masayoshi TSUZUKI <tsudukim@oss.nttdata.co.jp>

Closes #5347 from tsudukim/feature/SPARK-6568 and squashes the following commits:

9180aaf [Masayoshi TSUZUKI] [SPARK-6568] spark-shell.cmd --jars option does not accept the jar that has space in its path

0.7 fixes a bug that's pretty useful, i.e. inline functions no longer return explicit type definition.

Author: Reynold Xin <rxin@databricks.com>

Closes #5399 from rxin/style0.7 and squashes the following commits:

54c41b2 [Reynold Xin] Actually update the version.
09c759c [Reynold Xin] [SPARK-6750] Upgrade ScalaStyle to 0.7.

Invoking .size on arrays is valid, but requires an implicit conversion to SeqLike. This incurs a compile time overhead and more importantly a runtime overhead, as the Array must be wrapped before the method can be invoked. For example, the difference in generated byte code is:

  public int withSize();
    Code:
       0: getstatic     #23                 // Field scala/Predef$.MODULE$:Lscala/Predef$;
       3: aload_0
       4: invokevirtual #25                 // Method array:()[I
       7: invokevirtual #29                 // Method scala/Predef$.intArrayOps:([I)Lscala/collection/mutable/ArrayOps;
      10: invokeinterface #34,  1           // InterfaceMethod scala/collection/mutable/ArrayOps.size:()I
      15: ireturn

  public int withLength();
    Code:
       0: aload_0
       1: invokevirtual #25                 // Method array:()[I
       4: arraylength
       5: ireturn

Author: sksamuel <sam@sksamuel.com>

Closes #5376 from sksamuel/master and squashes the following commits:

77ec261 [sksamuel] Replace use of .size with .length for Arrays.

Author: Vinod K C <vinod.kc@huawei.com>

Closes #5384 from vinodkc/Suppression_Scala_existential_code and squashes the following commits:

82a3a1f [Vinod K C] Added scala.language.existentials

https://issues.apache.org/jira/browse/SPARK-3591

The output after this patch:
>doggie153:/opt/oss/spark-1.3.0-bin-hadoop2.4/bin # ./spark-submit  --class org.apache.spark.examples.SparkPi --master yarn-cluster ../lib/spark-examples*.jar
15/03/31 21:15:25 WARN NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
15/03/31 21:15:25 INFO RMProxy: Connecting to ResourceManager at doggie153/10.177.112.153:8032
15/03/31 21:15:25 INFO Client: Requesting a new application from cluster with 4 NodeManagers
15/03/31 21:15:25 INFO Client: Verifying our application has not requested more than the maximum memory capability of the cluster (8192 MB per container)
15/03/31 21:15:25 INFO Client: Will allocate AM container, with 896 MB memory including 384 MB overhead
15/03/31 21:15:25 INFO Client: Setting up container launch context for our AM
15/03/31 21:15:25 INFO Client: Preparing resources for our AM container
15/03/31 21:15:26 INFO Client: Uploading resource file:/opt/oss/spark-1.3.0-bin-hadoop2.4/lib/spark-assembly-1.4.0-SNAPSHOT-hadoop2.4.1.jar -> hdfs://doggie153:9000/user/root/.sparkStaging/application_1427257505534_0016/spark-assembly-1.4.0-SNAPSHOT-hadoop2.4.1.jar
15/03/31 21:15:27 INFO Client: Uploading resource file:/opt/oss/spark-1.3.0-bin-hadoop2.4/lib/spark-examples-1.3.0-hadoop2.4.0.jar -> hdfs://doggie153:9000/user/root/.sparkStaging/application_1427257505534_0016/spark-examples-1.3.0-hadoop2.4.0.jar
15/03/31 21:15:28 INFO Client: Setting up the launch environment for our AM container
15/03/31 21:15:28 INFO SecurityManager: Changing view acls to: root
15/03/31 21:15:28 INFO SecurityManager: Changing modify acls to: root
15/03/31 21:15:28 INFO SecurityManager: SecurityManager: authentication disabled; ui acls disabled; users with view permissions: Set(root); users with modify permissions: Set(root)
15/03/31 21:15:28 INFO Client: Submitting application 16 to ResourceManager
15/03/31 21:15:28 INFO YarnClientImpl: Submitted application application_1427257505534_0016
15/03/31 21:15:28 INFO Client: ... waiting before polling ResourceManager for application state
15/03/31 21:15:33 INFO Client: ... polling ResourceManager for application state
15/03/31 21:15:33 INFO Client: Application report for application_1427257505534_0016 (state: RUNNING)
15/03/31 21:15:33 INFO Client:
         client token: N/A
         diagnostics: N/A
         ApplicationMaster host: doggie157
         ApplicationMaster RPC port: 0
         queue: default
         start time: 1427807728307
         final status: UNDEFINED
         tracking URL: http://doggie153:8088/proxy/application_1427257505534_0016/
         user: root

/cc andrewor14

Author: WangTaoTheTonic <wangtao111@huawei.com>

Closes #5297 from WangTaoTheTonic/SPARK-3591 and squashes the following commits:

c76d232 [WangTaoTheTonic] wrap lines
16c90a8 [WangTaoTheTonic] move up lines to avoid duplicate
fea390d [WangTaoTheTonic] log failed/killed report, style and comment
be1cc2e [WangTaoTheTonic] reword
f0bc54f [WangTaoTheTonic] minor: expose appid in excepiton messages
ba9b22b [WangTaoTheTonic] wrong config name
e1a4013 [WangTaoTheTonic] revert to the old version and do some robust
19706c0 [WangTaoTheTonic] add a config to control whether to forget
0cbdce8 [WangTaoTheTonic] fire and forget for YARN cluster mode

Example of Graph#aggregateMessages has error.
Since aggregateMessages is a method of Graph, It should be written "rawGraph.aggregateMessages"

Author: Sasaki Toru <sasakitoa@nttdata.co.jp>

Closes #5388 from sasakitoa/aggregateMessagesExample and squashes the following commits:

b1d631b [Sasaki Toru] Example of Graph#aggregateMessages has error

The spark_ec2.py script uses public_dns_name everywhere in the script except for testing ssh availability, which is done using the public ip address of the instances. This breaks the script for users who are deploying the cluster with a private-network-only security group. The fix is to use public_dns_name in the remaining place.

Author: Matt Aasted <aasted@twitch.tv>

Closes #5302 from aasted/master and squashes the following commits:

60cf6ee [Matt Aasted] [SPARK-6636] Use public DNS hostname everywhere in spark_ec2.py

Currently, the driver's executorId is set to `<driver>`. This choice of ID was present in older Spark versions, but it has started to cause problems now that executorIds are used in more contexts, such as Ganglia metric names or driver thread-dump links the web UI. The angle brackets must be escaped when embedding this ID in XML or as part of URLs and this has led to multiple problems:

- https://issues.apache.org/jira/browse/SPARK-6484
- https://issues.apache.org/jira/browse/SPARK-4313

The simplest solution seems to be to change this id to something that does not contain any special characters, such as `driver`.

I'm not sure whether we can perform this change in a patch release, since this ID may be considered a stable API by metrics users, but it's probably okay to do this in a major release as long as we document it in the release notes.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #5372 from JoshRosen/driver-id-fix and squashes the following commits:

42d3c10 [Josh Rosen] Clarify comment
0c5d04b [Josh Rosen] Add backwards-compatibility in BlockManagerId.isDriver
7ff12e0 [Josh Rosen] Change SparkContext.DRIVER_IDENTIFIER from <driver> to driver

The function uses .substring(0, X), which will trigger OutOfBoundsException if string length is less than X. A better way to do this is to use startsWith, which won't error out in this case.

Author: Volodymyr Lyubinets <vlyubin@gmail.com>

Closes #5378 from vlyubin/quirks and squashes the following commits:

504e8e0 [Volodymyr Lyubinets] Minor fix for DriverQuirks get

Use Iterators in columnSimilarities to allow mapPartitionsWithIndex to spill to disk. This could happen in a dense and large column - this way Spark can spill the pairs onto disk instead of building all the pairs before handing them to Spark.

Another PR coming to update documentation.

Author: Reza Zadeh <reza@databricks.com>

Closes #5364 from rezazadeh/optmemsim and squashes the following commits:

47c90ba [Reza Zadeh] Iterators in columnSimilarities for flatMap

Reduce "is the same as ending offset" message to INFO level per JIRA discussion

Author: Sean Owen <sowen@cloudera.com>

Closes #5366 from srowen/SPARK-6569 and squashes the following commits:

8a5b992 [Sean Owen] Reduce "is the same as ending offset" message to INFO level per JIRA discussion

added equivalent script to load-spark-env.sh

Author: Masayoshi TSUZUKI <tsudukim@oss.nttdata.co.jp>

Closes #5328 from tsudukim/feature/SPARK-6673 and squashes the following commits:

aaefb19 [Masayoshi TSUZUKI] removed dust.
be3405e [Masayoshi TSUZUKI] [SPARK-6673] spark-shell.cmd can't start in Windows even when spark was built

This is the second PR for [SPARK-6602]. It updated MapOutputTrackerMasterActor and its unit tests.

cc rxin

Author: zsxwing <zsxwing@gmail.com>

Closes #5371 from zsxwing/rpc-rewrite-part2 and squashes the following commits:

fcf3816 [zsxwing] Fix the code style
4013a22 [zsxwing] Add doc for uncaught exceptions in RpcEnv
93c6c20 [zsxwing] Add an example of UnserializableException and add ErrorMonitor to monitor errors from Akka
134fe7b [zsxwing] Update MapOutputTrackerMasterActor to MapOutputTrackerMasterEndpoint

Add below methods in pyspark for MultivariateStatisticalSummary
- normL1
- normL2

Author: lewuathe <lewuathe@me.com>

Closes #5359 from Lewuathe/SPARK-6262 and squashes the following commits:

cbe439e [lewuathe] Implement missing methods for MultivariateStatisticalSummary

This PR replaced the following `Actor`s to `RpcEndpoint`:

1. HeartbeatReceiver
1. ExecutorActor
1. BlockManagerMasterActor
1. BlockManagerSlaveActor
1. CoarseGrainedExecutorBackend and subclasses
1. CoarseGrainedSchedulerBackend.DriverActor

This is the first PR. I will split the work of SPARK-6602 to several PRs for code review.

Author: zsxwing <zsxwing@gmail.com>

Closes #5268 from zsxwing/rpc-rewrite and squashes the following commits:

287e9f8 [zsxwing] Fix the code style
26c56b7 [zsxwing] Merge branch 'master' into rpc-rewrite
9cc825a [zsxwing] Rmove setupThreadSafeEndpoint and add ThreadSafeRpcEndpoint
30a9036 [zsxwing] Make self return null after stopping RpcEndpointRef; fix docs and error messages
705245d [zsxwing] Fix some bugs after rebasing the changes on the master
003cf80 [zsxwing] Update CoarseGrainedExecutorBackend and CoarseGrainedSchedulerBackend to use RpcEndpoint
7d0e6dc [zsxwing] Update BlockManagerSlaveActor to use RpcEndpoint
f5d6543 [zsxwing] Update BlockManagerMaster to use RpcEndpoint
30e3f9f [zsxwing] Update ExecutorActor to use RpcEndpoint
478b443 [zsxwing] Update HeartbeatReceiver to use RpcEndpoint

'(' and ')' are special characters used in Parquet schema for type annotation. When we run an aggregation query, we will obtain attribute name such as "MAX(a)".

If we directly store the generated DataFrame as Parquet file, it causes failure when reading and parsing the stored schema string.

Several methods can be adopted to solve this. This pr uses a simplest one to just replace attribute names before generating Parquet schema based on these attributes.

Another possible method might be modifying all aggregation expression names from "func(column)" to "func[column]".

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #5263 from viirya/parquet_aggregation_name and squashes the following commits:

2d70542 [Liang-Chi Hsieh] Address comment.
463dff4 [Liang-Chi Hsieh] Instead of replacing special chars, showing error message to user to suggest using Alias.
1de001d [Liang-Chi Hsieh] Replace special characters '(' and ')' of Parquet schema.

Author: Yin Huai <yhuai@databricks.com>

Closes #5353 from yhuai/wrongFS and squashes the following commits:

849603b [Yin Huai] Not use deprecated method.
6d6ae34 [Yin Huai] Use path.makeQualified.

Author: Davies Liu <davies@databricks.com>

Closes #5356 from davies/flaky and squashes the following commits:

08955f4 [Davies Liu] disable flaky test

[SPARK-6647][SQL] Make trait StringComparison as BinaryPredicate and fix unit tests of string data source Filter

Now trait `StringComparison` is a `BinaryExpression`. In fact, it should be a `BinaryPredicate`.

By making `StringComparison` as `BinaryPredicate`, we can throw error when a `expressions.Predicate` can't translate to a data source `Filter` in function `selectFilters`.

Without this modification, because we will wrap a `Filter` outside the scanned results in `pruneFilterProjectRaw`, we can't detect about something is wrong in translating predicates to filters in `selectFilters`.

The unit test of #5285 demonstrates such problem. In that pr, even `expressions.Contains` is not properly translated to `sources.StringContains`, the filtering is still performed by the `Filter` and so the test passes.

Of course, by doing this modification, all `expressions.Predicate` classes need to have its data source `Filter` correspondingly.

There is a small bug in `FilteredScanSuite` for doing `StringEndsWith` filter. This pr also fixes it.

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #5309 from viirya/translate_predicate and squashes the following commits:

b176385 [Liang-Chi Hsieh] Address comment.
275a493 [Liang-Chi Hsieh] More properly test for StringStartsWith, StringEndsWith and StringContains.
caf2347 [Liang-Chi Hsieh] Make trait StringComparison as BinaryPredicate and throw error when Predicate can't translate to data source Filter.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #5340 from vanzin/SPARK-6688 and squashes the following commits:

ccfddd9 [Marcelo Vanzin] Resolve at the source.
20d2a34 [Marcelo Vanzin] [SPARK-6688] [core] Always use resolved URIs in EventLoggingListener.

[SPARK-6640][Core] Fix the race condition of creating HeartbeatReceiver and retrieving HeartbeatReceiver

This PR moved the code of creating `HeartbeatReceiver` above the code of creating `schedulerBackend` to resolve the race condition.

Author: zsxwing <zsxwing@gmail.com>

Closes #5306 from zsxwing/SPARK-6640 and squashes the following commits:

840399d [zsxwing] Don't send TaskScheduler through Akka
a90616a [zsxwing] Fix docs
dd202c7 [zsxwing] Fix typo
d7c250d [zsxwing] Fix the race condition of creating HeartbeatReceiver and retrieving HeartbeatReceiver

I've added a timeout and retry loop around the SparkContext shutdown code that should fix this deadlock. If a SparkContext shutdown is in progress when another thread comes knocking, it will wait for 10 seconds for the lock, then fall through where the outer loop will re-submit the request.

Author: Ilya Ganelin <ilya.ganelin@capitalone.com>

Closes #5277 from ilganeli/SPARK-6492 and squashes the following commits:

8617a7e [Ilya Ganelin] Resolved merge conflict
2fbab66 [Ilya Ganelin] Added MIMA Exclude
a0e2c70 [Ilya Ganelin] Deleted stale imports
fa28ce7 [Ilya Ganelin] reverted to just having a single stopped
76fc825 [Ilya Ganelin] Updated to use atomic booleans instead of the synchronized vars
6e8a7f7 [Ilya Ganelin] Removing unecessary null check for now since i'm not fixing stop ordering yet
cdf7073 [Ilya Ganelin] [SPARK-6492] Moved stopped=true back to the start of the shutdown sequence so this can be addressed in a seperate PR
7fb795b [Ilya Ganelin] Spacing
b7a0c5c [Ilya Ganelin] Import ordering
df8224f [Ilya Ganelin] Added comment for added lock
343cb94 [Ilya Ganelin] [SPARK-6492] Added timeout/retry logic to fix a deadlock in SparkContext shutdown

   When union non-decimal types with decimals, we use the following rules:
      - FIRST `intTypeToFixed`, then fixed union decimals with precision/scale p1/s2 and p2/s2  will be promoted to
      DecimalType(max(p1, p2), max(s1, s2))
      - FLOAT and DOUBLE cause fixed-length decimals to turn into DOUBLE (this is the same as Hive,
      but note that unlimited decimals are considered bigger than doubles in WidenTypes)

Author: guowei2 <guowei2@asiainfo.com>

Closes #4004 from guowei2/SPARK-5203 and squashes the following commits:

ff50f5f [guowei2] fix code style
11df1bf [guowei2] fix decimal union with double, double->Decimal(15,15)
0f345f9 [guowei2] fix structType merge with decimal
101ed4d [guowei2] fix build error after rebase
0b196e4 [guowei2] code style
fe2c2ca [guowei2] handle union decimal precision in 'DecimalPrecision'
421d840 [guowei2] fix union types for decimal precision
ef2c661 [guowei2] fix union with different decimal type

Just fix a typo.

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #5352 from viirya/fix_a_typo and squashes the following commits:

303b2d2 [Liang-Chi Hsieh] Fix typo.

This is the sub-task of SPARK-6254.
Wrap missing method for `Word2Vec` and `Word2VecModel`.

Author: lewuathe <lewuathe@me.com>

Closes #5296 from Lewuathe/SPARK-6615 and squashes the following commits:

f14c304 [lewuathe] Reorder tests
1d326b9 [lewuathe] Merge master
e2bedfb [lewuathe] Modify test cases
afb866d [lewuathe] [SPARK-6615] Python API for Word2Vec

There's no corresponding printing in linear regression. Here was my previous PR (something weird happened and I can't reopen it) https://github.com/apache/spark/pull/5272

Author: Omede Firouz <ofirouz@palantir.com>

Closes #5338 from oefirouz/println and squashes the following commits:

3f3dbf4 [Omede Firouz] [MLLIB] Remove println

If there is a failure in the Hadoop backend while calling
writer.write, we should remember this original exception,
and try to call writer.close(), but if that fails as well,
still report the original exception.

Note that, if writer.write fails, it is likely that writer
was left in an invalid state, and so actually makes it more
likely that writer.close will also fail. Which just increases
the chances for writer.write's exception to be suppressed.

This patch introduces an admittedly potentially too cute
Utils.tryWithSafeFinally method to handle the try/finally
gyrations.

Author: Stephen Haberman <stephen@exigencecorp.com>

Closes #5223 from stephenh/do_not_suppress_writer_exception and squashes the following commits:

c7ad53f [Stephen Haberman] [SPARK-6560][CORE] Do not suppress exceptions from writer.write.

This builds on my earlier pull requests and turns on the explicit type checking in scalastyle.

Author: Reynold Xin <rxin@databricks.com>

Closes #5342 from rxin/SPARK-6428 and squashes the following commits:

7b531ab [Reynold Xin] import ordering
2d9a8a5 [Reynold Xin] jl
e668b1c [Reynold Xin] override
9b9e119 [Reynold Xin] Parenthesis.
82e0cf5 [Reynold Xin] [SPARK-6428] Turn on explicit type checking for public methods.