FLUME-2945. Bump java target version to 1.8

- Removed the unsupported PermSize and MaxPermSize settings from .travis.yml
- Updated DEVNOTES, README and Flume User Guide
- Removed the maven-compiler-plugin from the taildir-source subproject
- Changed the sourceJavaVersion and targetJavaVersion to 1.8 in the root pom.xml

(Lior Zeno via Denes Arvay)

Author: liorze

.travis.yml

@@ -21,4 +21,4 @@ before_install:
 install:
   - # Skip mvn install. See https://docs.travis-ci.com/user/languages/java/
 script:
-  - MAVEN_OPTS="-Xms512m -Xmx1024m -XX:PermSize=256m -XX:MaxPermSize=512m" mvn clean install -DskipTests
+  - MAVEN_OPTS="-Xms512m -Xmx1024m" mvn clean install -DskipTests

DEVNOTES

@@ -41,17 +41,7 @@ to most devs are "compile" -> "test" -> "package" -> "install".
 
 Set MAVEN_OPTS to give the Flume build enough RAM to build.
 
-  export MAVEN_OPTS="-Xmx512M -XX:MaxPermSize=512M"
-
-Note: If you see a permgen error (below), you need to increase the perm gen size.
-
-[ERROR] PermGen space -> [Help 1]
-[ERROR] 
-[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
-[ERROR] Re-run Maven using the -X switch to enable full debug logging.
-[ERROR] 
-[ERROR] For more information about the errors and possible solutions, please read the following articles:
-[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/OutOfMemoryError
+  export MAVEN_OPTS="-Xms512m -Xmx1024m"
 
 Builds
 ------

README.md

@@ -55,13 +55,13 @@ Bug and Issue tracker.
 
 Compiling Flume requires the following tools:
 
-* Oracle Java JDK 1.7
+* Oracle Java JDK 1.8
 * Apache Maven 3.x
 
 Note: The Apache Flume build requires more memory than the default configuration.
 We recommend you set the following Maven options:
 
-export MAVEN_OPTS="-Xms512m -Xmx1024m -XX:PermSize=256m -XX:MaxPermSize=512m"
+`export MAVEN_OPTS="-Xms512m -Xmx1024m"`
 
 To compile Flume and build a distribution tarball, run `mvn install` from the
 top level directory. The artifacts will be placed under `flume-ng-dist/target/`.

conf/flume-env.sh.template

@@ -19,7 +19,7 @@
 
 # Enviroment variables can be set here.
 
-# export JAVA_HOME=/usr/lib/jvm/java-6-sun
+# export JAVA_HOME=/usr/lib/jvm/java-8-oracle
 
 # Give Flume more memory and pre-allocate, enable remote monitoring via JMX
 # export JAVA_OPTS="-Xms100m -Xmx2000m -Dcom.sun.management.jmxremote"

flume-ng-doc/sphinx/FlumeUserGuide.rst

@@ -50,7 +50,7 @@ in the latest architecture.
 System Requirements
 -------------------
 
-#. Java Runtime Environment - Java 1.7 or later
+#. Java Runtime Environment - Java 1.8 or later
 #. Memory - Sufficient memory for configurations used by sources, channels or sinks
 #. Disk Space - Sufficient disk space for configurations used by channels or sinks
 #. Directory Permissions - Read/Write permissions for directories used by agent

flume-ng-sources/flume-taildir-source/pom.xml

@@ -30,20 +30,6 @@ limitations under the License.
   <artifactId>flume-taildir-source</artifactId>
   <name>Flume Taildir Source</name>
 
-  <build>
-    <plugins>
-      <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-compiler-plugin</artifactId>
-        <version>2.3.2</version>
-        <configuration>
-          <source>1.7</source>
-          <target>1.7</target>
-        </configuration>
-      </plugin>
-    </plugins>
-  </build>
-
   <dependencies>
     <dependency>
       <groupId>org.apache.flume</groupId>

pom.xml

@@ -37,8 +37,8 @@ limitations under the License.
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
     <!-- Java compiler configuration -->
-    <sourceJavaVersion>1.7</sourceJavaVersion>
-    <targetJavaVersion>1.7</targetJavaVersion>
+    <sourceJavaVersion>1.8</sourceJavaVersion>
+    <targetJavaVersion>1.8</targetJavaVersion>
 
     <!-- defaults for flaky test and focused test exclusions -->
     <test.exclude.pattern>$</test.exclude.pattern> <!-- junk pattern -->