update to java 8

Author: BCaxelbecker

pom.xml

@@ -26,7 +26,7 @@
 		<arangodb.velocypack.version>1.4.1</arangodb.velocypack.version>
 
 		<!-- provided -->
-		<httpclient.version>4.5.1</httpclient.version>
+		<httpclient.version>4.5.7</httpclient.version>
 
 		<!-- test -->
 		<logback-classic.version>1.1.3</logback-classic.version>
@@ -74,10 +74,34 @@
 
 	<build>
 		<plugins>
+		
+			<plugin>
+				<inherited>true</inherited>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-enforcer-plugin</artifactId>
+				<version>3.0.0-M2</version>
+				<executions>
+					<execution>
+						<id>enforce-maven-3</id>
+						<goals>
+							<goal>enforce</goal>
+						</goals>
+						<configuration>
+							<rules>
+								<requireMavenVersion>
+									<version>3.0.5</version>
+								</requireMavenVersion>
+							</rules>
+							<fail>true</fail>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+		
 			<plugin>
 				<groupId>org.sonatype.plugins</groupId>
 				<artifactId>nexus-staging-maven-plugin</artifactId>
-				<version>1.6.5</version>
+				<version>1.6.8</version>
 				<extensions>true</extensions>
 				<configuration>
 					<serverId>ossrh</serverId>
@@ -90,7 +114,6 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-assembly-plugin</artifactId>
-				<version>2.4.1</version>
 				<executions>
 					<execution>
 						<id>assembly</id>
@@ -115,18 +138,16 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-compiler-plugin</artifactId>
-				<version>3.2</version>
 				<configuration>
-					<source>1.6</source>
-					<target>1.6</target>
+					<source>1.8</source>
+					<target>1.8</target>
 					<compilerArgument></compilerArgument>
 				</configuration>
 			</plugin>
 
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-resources-plugin</artifactId>
-				<version>2.7</version>
 				<configuration>
 					<encoding>UTF-8</encoding>
 				</configuration>
@@ -135,7 +156,6 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-source-plugin</artifactId>
-				<version>2.4</version>
 				<executions>
 					<execution>
 						<goals>
@@ -148,7 +168,6 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-javadoc-plugin</artifactId>
-				<version>2.9.1</version>
 				<executions>
 					<execution>
 						<id>attach-javadocs</id>
@@ -165,7 +184,6 @@
 
 			<plugin>
 				<artifactId>maven-surefire-plugin</artifactId>
-				<version>2.19.1</version>
 				<configuration>
 					<includes>
 						<include>**/*Test.java</include>
@@ -176,7 +194,6 @@
 
 			<plugin>
 				<artifactId>maven-deploy-plugin</artifactId>
-				<version>2.8.2</version>
 				<configuration>
 					<uniqueVersion>false</uniqueVersion>
 					<retryFailedDeploymentCount>10</retryFailedDeploymentCount>
@@ -186,7 +203,6 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-gpg-plugin</artifactId>
-				<version>1.5</version>
 				<executions>
 					<execution>
 						<id>sign-artifacts</id>