[SPARK-7733] [CORE] [BUILD] Update build, code to use Java 7 for 1.5.0+

Update build to use Java 7, and remove some comments and special-case support for Java 6.

Author: Sean Owen <sowen@cloudera.com>

Closes #6265 from srowen/SPARK-7733 and squashes the following commits:

59bda4e [Sean Owen] Update build to use Java 7, and remove some comments and special-case support for Java 6

3 files changed, 3 insertions, 7 deletions

diff --git a/docs/building-spark.md b/docs/building-spark.md
index 78cb9086f9..2128fdffec 100644
--- a/docs/building-spark.md
+++ b/docs/building-spark.md
@@ -7,11 +7,7 @@ redirect_from: "building-with-maven.html"
 * This will become a table of contents (this text will be scraped).
 {:toc}
 
-Building Spark using Maven requires Maven 3.0.4 or newer and Java 6+.
-
-**Note:** Building Spark with Java 7 or later can create JAR files that may not be
-readable with early versions of Java 6, due to the large number of files in the JAR
-archive. Build with Java 6 if this is an issue for your deployment.
+Building Spark using Maven requires Maven 3.0.4 or newer and Java 7+.
 
 # Building with `build/mvn`
 
diff --git a/docs/index.md b/docs/index.md
index fac071da81..7939657915 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -20,7 +20,7 @@ Spark runs on both Windows and UNIX-like systems (e.g. Linux, Mac OS). It's easy
 locally on one machine --- all you need is to have `java` installed on your system `PATH`,
 or the `JAVA_HOME` environment variable pointing to a Java installation.
 
-Spark runs on Java 6+, Python 2.6+ and R 3.1+. For the Scala API, Spark {{site.SPARK_VERSION}} uses
+Spark runs on Java 7+, Python 2.6+ and R 3.1+. For the Scala API, Spark {{site.SPARK_VERSION}} uses
 Scala {{site.SCALA_BINARY_VERSION}}. You will need to use a compatible Scala version 
 ({{site.SCALA_BINARY_VERSION}}.x).
 
diff --git a/docs/programming-guide.md b/docs/programming-guide.md
index 10f474f237..d5ff416fe8 100644
--- a/docs/programming-guide.md
+++ b/docs/programming-guide.md
@@ -54,7 +54,7 @@ import org.apache.spark.SparkConf
 
 <div data-lang="java"  markdown="1">
 
-Spark {{site.SPARK_VERSION}} works with Java 6 and higher. If you are using Java 8, Spark supports
+Spark {{site.SPARK_VERSION}} works with Java 7 and higher. If you are using Java 8, Spark supports
 [lambda expressions](http://docs.oracle.com/javase/tutorial/java/javaOO/lambdaexpressions.html)
 for concisely writing functions, otherwise you can use the classes in the
 [org.apache.spark.api.java.function](api/java/index.html?org/apache/spark/api/java/function/package-summary.html) package.