## What changes were proposed in this pull request?

Since SPARK-13220(Deprecate "yarn-client" and "yarn-cluster"), YarnClusterSuite doesn't test "yarn cluster" mode correctly.
This pull request fixes it.

## How was this patch tested?
Unit test

(If this patch involves UI changes, please attach a screenshot; otherwise, remove this)

Author: peng.zhang <peng.zhang@xiaomi.com>

Closes #13836 from renozhang/SPARK-16125-test-yarn-cluster-mode.

## What changes were proposed in this pull
(Paste from JIRA issue.)
As a follow up for SPARK-15697, I have following semantics for `:reset` command.
On `:reset` we forget all that user has done but not the initialization of spark. To avoid confusion or make it more clear, we show the message `spark` and `sc` are not erased, infact they are in same state as they were left by previous operations done by the user.
While doing above, somewhere I felt that this is not usually what reset means. But an accidental shutdown of a cluster can be very costly, so may be in that sense this is less surprising and still useful.

## How was this patch tested?

Manually, by calling `:reset` command, by both altering the state of SparkContext and creating some local variables.

Author: Prashant Sharma <prashant@apache.org>
Author: Prashant Sharma <prashsh1@in.ibm.com>

Closes #13661 from ScrapCodes/repl-reset-command.

When `--packages` is specified with spark-shell the classes from those packages cannot be found, which I think is due to some of the changes in SPARK-12343.

Tested manually with both scala 2.10 and 2.11 repls.

vanzin davies can you guys please review?

Author: Marcelo Vanzin <vanzin@cloudera.com>
Author: Nezih Yigitbasi <nyigitbasi@netflix.com>

Closes #13709 from nezihyigitbasi/SPARK-15782.

This reverts commit 4df8df5c.

## What changes were proposed in this pull request?

When `--packages` is specified with `spark-shell` the classes from those packages cannot be found, which I think is due to some of the changes in `SPARK-12343`. In particular `SPARK-12343` removes a line that sets the `spark.jars` system property in client mode, which is used by the repl main class to set the classpath.

## How was this patch tested?

Tested manually.

This system property is used by the repl to populate its classpath. If
this is not set properly the classes for external packages cannot be
found.

tgravescs vanzin as you may be familiar with this part of the code.

Author: Nezih Yigitbasi <nyigitbasi@netflix.com>

Closes #13527 from nezihyigitbasi/repl-fix.

## What changes were proposed in this pull request?

Unblock some of the useful repl commands. like, "implicits", "javap", "power", "type", "kind". As they are useful and fully functional and part of scala/scala project, I see no harm in having them either.

Verbatim paste form JIRA description.
"implicits", "javap", "power", "type", "kind" commands in repl are blocked. However, they work fine in all cases I have tried. It is clear we don't support them as they are part of the scala/scala repl project. What is the harm in unblocking them, given they are useful ?
In previous versions of spark we disabled these commands because it was difficult to support them without customization and the associated maintenance. Since the code base of scala repl was actually ported and maintained under spark source. Now that is not the situation and one can benefit from these commands in Spark REPL as much as in scala repl.

## How was this patch tested?
Existing tests and manual, by trying out all of the above commands.

P.S. Symantics of reset are to be discussed in a separate issue.

Author: Prashant Sharma <prashsh1@in.ibm.com>

Closes #13437 from ScrapCodes/SPARK-15697/repl-unblock-commands.

Description from JIRA.
In ReplSuite, for a test that can be tested well on just local should not really have to start a local-cluster. And similarly a test is in-sufficiently run if it's actually fixing a problem related to a distributed run in environment with local run.

Existing tests.

Author: Prashant Sharma <prashsh1@in.ibm.com>

Closes #13574 from ScrapCodes/SPARK-15841/repl-suite-fix.

## What changes were proposed in this pull request?

This PR corrects the remaining cases for using old accumulators.

This does not change some old accumulator usages below:

- `ImplicitSuite.scala` - Tests dedicated to old accumulator, for implicits with `AccumulatorParam`

- `AccumulatorSuite.scala` -  Tests dedicated to old accumulator

- `JavaSparkContext.scala` - For supporting old accumulators for Java API.

- `debug.package.scala` - Usage with `HashSet[String]`. Currently, it seems no implementation for this. I might be able to write an anonymous class for this but I didn't because I think it is not worth writing a lot of codes only for this.

- `SQLMetricsSuite.scala` - This uses the old accumulator for checking type boxing. It seems new accumulator does not require type boxing for this case whereas the old one requires (due to the use of generic).

## How was this patch tested?

Existing tests cover this.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #13434 from HyukjinKwon/accum.

## What changes were proposed in this pull request?
This PR change REPL/Main to check this property `spark.sql.catalogImplementation` to decide if `enableHiveSupport `should be called.

If `spark.sql.catalogImplementation` is set to `hive`, and hive classes are built, Spark will use Hive support.
Other wise, Spark will create a SparkSession with in-memory catalog support.

## How was this patch tested?
Run the REPL component test.

Author: xin Wu <xinwu@us.ibm.com>
Author: Xin Wu <xinwu@us.ibm.com>

Closes #13088 from xwu0226/SPARK-15236.

## What changes were proposed in this pull request?
At https://github.com/aunkrig/janino/blob/janino_2.7.8/janino/src/org/codehaus/janino/ClassLoaderIClassLoader.java#L80-L85, Janino's classloader throws the exception when its parent throws a ClassNotFoundException with a cause set. However, it does not throw the exception when there is no cause set. Seems we need to use a special ClassLoader to wrap the actual parent classloader set to Janino handle this behavior.

## How was this patch tested?
I have reverted the workaround made by https://issues.apache.org/jira/browse/SPARK-11636 ( https://github.com/apache/spark/compare/master...yhuai:SPARK-15622?expand=1#diff-bb538fda94224dd0af01d0fd7e1b4ea0R81) and `test-only *ReplSuite -- -z "SPARK-2576 importing implicits"` still passes the test (without the change in `CodeGenerator`, this test does not pass with the change in `ExecutorClassLoader `).

Author: Yin Huai <yhuai@databricks.com>

Closes #13366 from yhuai/SPARK-15622.

## What changes were proposed in this pull request?

(See https://github.com/apache/spark/pull/12416 where most of this was already reviewed and committed; this is just the module structure and move part. This change does not move the annotations into test scope, which was the apparently problem last time.)

Rename `spark-test-tags` -> `spark-tags`; move common annotations like `Since` to `spark-tags`

## How was this patch tested?

Jenkins tests.

Author: Sean Owen <sowen@cloudera.com>

Closes #13074 from srowen/SPARK-15290.

## What changes were proposed in this pull request?

see https://github.com/apache/spark/pull/12873#discussion_r61993910. The problem is, if we create `SparkContext` first and then call `SparkSession.builder.enableHiveSupport().getOrCreate()`, we will reuse the existing `SparkContext` and the hive flag won't be set.

## How was this patch tested?

verified it locally.

Author: Wenchen Fan <wenchen@databricks.com>

Closes #12890 from cloud-fan/repl.

## What changes were proposed in this pull request?

Users should use the builder pattern instead.

## How was this patch tested?

Jenks.

Author: Andrew Or <andrew@databricks.com>

Closes #12873 from andrewor14/spark-session-constructor.

This reverts commit dae538a4.

## What changes were proposed in this pull request?

This PR adds `since` tag into the matrix and vector classes in spark-mllib-local.

## How was this patch tested?

Scala-style checks passed.

Author: Pravin Gadakh <prgadakh@in.ibm.com>

Closes #12416 from pravingadakh/SPARK-14613.

## What changes were proposed in this pull request?
This is a proposal to print the Spark Driver UI link when spark-shell is launched.

## How was this patch tested?
Launched spark-shell in local mode and cluster mode. Spark-shell console output included following line:
"Spark context Web UI available at <Spark web url>"

Author: Ergin Seyfe <eseyfe@fb.com>

Closes #12341 from seyfe/spark_console_display_webui_link.

## What changes were proposed in this pull request?

```
Spark context available as 'sc' (master = local[*], app id = local-1461283768192).
Spark session available as 'spark'.
Welcome to
      ____              __
     / __/__  ___ _____/ /__
    _\ \/ _ \/ _ `/ __/  '_/
   /___/ .__/\_,_/_/ /_/\_\   version 2.0.0-SNAPSHOT
      /_/

Using Scala version 2.11.8 (Java HotSpot(TM) 64-Bit Server VM, Java 1.7.0_51)
Type in expressions to have them evaluated.
Type :help for more information.

scala> sql("SHOW TABLES").collect()
16/04/21 17:09:39 WARN ObjectStore: Version information not found in metastore. hive.metastore.schema.verification is not enabled so recording the schema version 1.2.0
16/04/21 17:09:39 WARN ObjectStore: Failed to get database default, returning NoSuchObjectException
res0: Array[org.apache.spark.sql.Row] = Array([src,false])

scala> sql("SHOW TABLES").collect()
res1: Array[org.apache.spark.sql.Row] = Array([src,false])

scala> spark.createDataFrame(Seq((1, 1), (2, 2), (3, 3)))
res2: org.apache.spark.sql.DataFrame = [_1: int, _2: int]
```

Hive things are loaded lazily.

## How was this patch tested?

Manual.

Author: Andrew Or <andrew@databricks.com>

Closes #12589 from andrewor14/spark-session-repl.

## What changes were proposed in this pull request?
This is a follow-up to #12557, with the following changes:

1. Fixes some of the style issues.
2. Merges Signaling and SignalLogger into a new class called SignalUtils. It was pretty confusing to have Signaling and Signal in one file, and it was also confusing to have two classes named Signaling and one called the other.
3. Made logging registration idempotent.

## How was this patch tested?
N/A.

Author: Reynold Xin <rxin@databricks.com>

Closes #12605 from rxin/SPARK-10001.

## What changes were proposed in this pull request?

Improve signal handling to allow interrupting running tasks from the REPL (with Ctrl+C).
If no tasks are running or Ctrl+C is pressed twice, the signal is forwarded to the default handler resulting in the usual termination of the application.

This PR is a rewrite of -- and therefore closes #8216 -- as per piaozhexiu's request

## How was this patch tested?
Signal handling is not easily testable therefore no unit tests were added. Nevertheless, the new functionality is implemented in a best-effort approach, soft-failing in case signals aren't available on a specific OS.

Author: Jakob Odersky <jakob@odersky.com>

Closes #12557 from jodersky/SPARK-10001-sigint.

## What changes were proposed in this pull request?

This proposal removes the class `HttpServer`, with the changing of internal file/jar/class transmission to RPC layer, currently there's no code using this `HttpServer`, so here propose to remove it.

## How was this patch tested?

Unit test is verified locally.

Author: jerryshao <sshao@hortonworks.com>

Closes #12526 from jerryshao/SPARK-14725.

## What changes were proposed in this pull request?

When we clean a closure, if its outermost parent is not a closure, we won't clone and clean it as cloning user's objects is dangerous. However, if it's a REPL line object, which may carry a lot of unnecessary references(like hadoop conf, spark conf, etc.), we should clean it as it's not a user object.

This PR improves the check for user's objects to exclude REPL line object.

## How was this patch tested?

existing tests.

Author: Wenchen Fan <wenchen@databricks.com>

Closes #12327 from cloud-fan/closure.

## What changes were proposed in this pull request?

According to the [Spark Code Style Guide](https://cwiki.apache.org/confluence/display/SPARK/Spark+Code+Style+Guide) and [Scala Style Guide](http://docs.scala-lang.org/style/control-structures.html#curlybraces), we had better enforce the following rule.
  ```
  case: Always omit braces in case clauses.
  ```
This PR makes a new ScalaStyle rule, 'OmitBracesInCase', and enforces it to the code.

## How was this patch tested?

Pass the Jenkins tests (including Scala style checking)

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #12280 from dongjoon-hyun/SPARK-14508.

## What changes were proposed in this pull request?
When we first introduced Aggregators, we required the user of Aggregators to (implicitly) specify the encoders. It would actually make more sense to have the encoders be specified by the implementation of Aggregators, since each implementation should have the most state about how to encode its own data type.

Note that this simplifies the Java API because Java users no longer need to explicitly specify encoders for aggregators.

## How was this patch tested?
Updated unit tests.

Author: Reynold Xin <rxin@databricks.com>

Closes #12231 from rxin/SPARK-14451.

The current package name uses a dash, which is a little weird but seemed
to work. That is, until a new test tried to mock a class that references
one of those shaded types, and then things started failing.

Most changes are just noise to fix the logging configs.

For reference, SPARK-8815 also raised this issue, although at the time it
did not cause any issues in Spark, so it was not addressed.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #11941 from vanzin/SPARK-14134.

Just use the same test code as the 2.11 version, which seems to pass.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #12223 from vanzin/SPARK-14446.

## What changes were proposed in this pull request?

This PR aims to fix all Scala-Style multiline comments into Java-Style multiline comments in Scala codes.
(All comment-only changes over 77 files: +786 lines, −747 lines)

## How was this patch tested?

Manual.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #12130 from dongjoon-hyun/use_multiine_javadoc_comments.

## What changes were proposed in this pull request?

Spark Shell provides an easy way to use Spark in Scala environment. This PR adds `reset` command to a blocked list, also cleaned up according to the Scala coding style.
```scala
scala> sc
res0: org.apache.spark.SparkContext = org.apache.spark.SparkContext718fad24
scala> :reset
scala> sc
<console>:11: error: not found: value sc
       sc
       ^
```
If we blocks `reset`, Spark Shell works like the followings.
```scala
scala> :reset
reset: no such command.  Type :help for help.
scala> :re
re is ambiguous: did you mean :replay or :require?
```

## How was this patch tested?

Manual. Run `bin/spark-shell` and type `:reset`.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11920 from dongjoon-hyun/SPARK-14102.

## What changes were proposed in this pull request?

In https://github.com/apache/spark/pull/11410, we missed a corner case: define the inner class and use it in `Dataset` at the same time by using paste mode. For this case, the inner class and the `Dataset` are inside same line object, when we build the `Dataset`, we try to get outer pointer from line object, and it will fail because the line object is not initialized yet.

https://issues.apache.org/jira/browse/SPARK-13456?focusedCommentId=15209174&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15209174 is an example for this corner case.

This PR make the process of getting outer pointer from line object lazy, so that we can successfully build the `Dataset` and finish initializing the line object.

## How was this patch tested?

new test in repl suite.

Author: Wenchen Fan <wenchen@databricks.com>

Closes #11931 from cloud-fan/repl.

## What changes were proposed in this pull request?

case classes defined in REPL are wrapped by line classes, and we have a trick for scala 2.10 REPL to automatically register the wrapper classes to `OuterScope` so that we can use when create encoders.
However, this trick doesn't work right after we upgrade to scala 2.11, and unfortunately the tests are only in scala 2.10, which makes this bug hidden until now.

This PR moves the encoder tests to scala 2.11  `ReplSuite`, and fixes this bug by another approach(the previous trick can't port to scala 2.11 REPL): make `OuterScope` smarter that can detect classes defined in REPL and load the singleton of line wrapper classes automatically.

## How was this patch tested?

the migrated encoder tests in `ReplSuite`

Author: Wenchen Fan <wenchen@databricks.com>

Closes #11410 from cloud-fan/repl.

## What changes were proposed in this pull request?

Logging was made private in Spark 2.0. If we move it, then users would be able to create a Logging trait themselves to avoid changing their own code.

## How was this patch tested?

existing tests.

Author: Wenchen Fan <wenchen@databricks.com>

Closes #11764 from cloud-fan/logger.

Three different things were needed to get rid of spurious warnings:
- silence deprecation warnings when cloning configuration
- change the way SparkHadoopUtil instantiates SparkConf to silence
  warnings
- avoid creating new SparkConf instances where it's not needed.

On top of that, I changed the way that Logging.scala detects the repl;
now it uses a method that is overridden in the repl's Main class, and
the hack in Utils.scala is not needed anymore. This makes the 2.11 repl
behave like the 2.10 one and set the default log level to WARN, which
is a lot better. Previously, this wasn't working because the 2.11 repl
triggers log initialization earlier than the 2.10 one.

I also removed and simplified some other code in the 2.11 repl's Main
to avoid replicating logic that already exists elsewhere in Spark.

Tested the 2.11 repl in local and yarn modes.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #11510 from vanzin/SPARK-13626.

## What changes were proposed in this pull request?

Since the opening curly brace, '{', has many usages as discussed in [SPARK-3854](https://issues.apache.org/jira/browse/SPARK-3854), this PR adds a ScalaStyle rule to prevent '){' pattern  for the following majority pattern and fixes the code accordingly. If we enforce this in ScalaStyle from now, it will improve the Scala code quality and reduce review time.
```
// Correct:
if (true) {
  println("Wow!")
}

// Incorrect:
if (true){
   println("Wow!")
}
```
IntelliJ also shows new warnings based on this.

## How was this patch tested?

Pass the Jenkins ScalaStyle test.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11637 from dongjoon-hyun/SPARK-3854.

## What changes were proposed in this pull request?

This PR fixes typos in comments and testcase name of code.

## How was this patch tested?

manual.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11481 from dongjoon-hyun/minor_fix_typos_in_code.

## What changes were proposed in this pull request?

After SPARK-6990, `dev/lint-java` keeps Java code healthy and helps PR review by saving much time.
This issue aims remove unused imports from Java/Scala code and add `UnusedImports` checkstyle rule to help developers.

## How was this patch tested?
```
./dev/lint-java
./build/sbt compile
```

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11438 from dongjoon-hyun/SPARK-13583.

Now:

```
$ bin/spark-shell -i test.scala
NOTE: SPARK_PREPEND_CLASSES is set, placing locally compiled Spark classes ahead of assembly.
Setting default log level to "WARN".
To adjust logging level use sc.setLogLevel(newLevel).
16/01/29 17:37:38 WARN NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
16/01/29 17:37:39 INFO Main: Created spark context..
Spark context available as sc (master = local[*], app id = local-1454085459000).
16/01/29 17:37:39 INFO Main: Created sql context..
SQL context available as sqlContext.
Loading test.scala...
hello

Welcome to
      ____              __
     / __/__  ___ _____/ /__
    _\ \/ _ \/ _ `/ __/  '_/
   /___/ .__/\_,_/_/ /_/\_\   version 2.0.0-SNAPSHOT
      /_/

Using Scala version 2.11.7 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_45)
Type in expressions to have them evaluated.
Type :help for more information.
```

Author: Iulian Dragos <jaguarul@gmail.com>

Closes #10984 from dragos/issue/repl-eval-file.

This patch changes Spark's build to make Scala 2.11 the default Scala version. To be clear, this does not mean that Spark will stop supporting Scala 2.10: users will still be able to compile Spark for Scala 2.10 by following the instructions on the "Building Spark" page; however, it does mean that Scala 2.11 will be the default Scala version used by our CI builds (including pull request builds).

The Scala 2.11 compiler is faster than 2.10, so I think we'll be able to look forward to a slight speedup in our CI builds (it looks like it's about 2X faster for the Maven compile-only builds, for instance).

After this patch is merged, I'll update Jenkins to add new compile-only jobs to ensure that Scala 2.10 compilation doesn't break.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #10608 from JoshRosen/SPARK-6363.

Removes some duplicated code that was reintroduced during a merge.

Author: Jakob Odersky <jodersky@gmail.com>

Closes #10711 from jodersky/repl-2.11-duplicate.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #10582 from vanzin/SPARK-3873-tests.

Also included a few miscelaneous other modules that had very few violations.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #10532 from vanzin/SPARK-3873-streaming.

[SPARK-12311][CORE] Restore previous value of "os.arch" property in test suites after forcing to set specific value to "os.arch" property

Restore the original value of os.arch property after each test

Since some of tests forced to set the specific value to os.arch property, we need to set the original value.

Author: Kazuaki Ishizaki <ishizaki@jp.ibm.com>

Closes #10289 from kiszk/SPARK-12311.