Remove Guava dependency and update to Java 9 (#272)

Author: claudioweiler

parent/pom.xml

@@ -88,9 +88,12 @@ application while protecting against XSS.
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
-    <guava.version>30.1-jre</guava.version>
+    <maven.compiler.source>9</maven.compiler.source>
+    <maven.compiler.target>9</maven.compiler.target>
+    <maven.compiler.release>9</maven.compiler.release>
   </properties>
 
+
   <build>
     <pluginManagement>
       <plugins>
@@ -184,8 +187,8 @@ application while protecting against XSS.
           <artifactId>maven-compiler-plugin</artifactId>
           <version>3.3</version>
           <configuration>
-            <source>6</source>
-            <target>6</target>
+            <source>9</source>
+            <target>9</target>
           </configuration>
         </plugin>
         <plugin>
@@ -234,15 +237,10 @@ application while protecting against XSS.
 
   <dependencyManagement>
     <dependencies>
-      <dependency>
-        <groupId>com.google.guava</groupId>
-        <artifactId>guava</artifactId>
-        <version>${guava.version}</version>
-      </dependency>
       <dependency>
         <groupId>commons-codec</groupId>
         <artifactId>commons-codec</artifactId>
-        <version>[1.4,)</version>
+        <version>[1.15,)</version>
       </dependency>
       <dependency>
         <groupId>com.google.code.findbugs</groupId>

pom.xml

@@ -60,6 +60,11 @@
       <plugin>
         <groupId>org.apache.felix</groupId>
         <artifactId>maven-bundle-plugin</artifactId>
+        <configuration>
+          <instructions>
+            <Export-Package>org.owasp.html</Export-Package>
+          </instructions>
+        </configuration>
       </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
@@ -81,10 +86,6 @@
   </build>
 
   <dependencies>
-    <dependency>
-      <groupId>com.google.guava</groupId>
-      <artifactId>guava</artifactId>
-    </dependency>
     <dependency>
       <groupId>commons-codec</groupId>
       <artifactId>commons-codec</artifactId>

src/main/java/org/owasp/html/AttributePolicy.java

@@ -28,9 +28,8 @@
 
 package org.owasp.html;
 
-import com.google.common.base.Optional;
-import com.google.common.collect.ImmutableList;
-
+import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 
 import javax.annotation.CheckReturnValue;
@@ -91,11 +90,11 @@ static final class AttributePolicyJoiner
       }
 
       @Override
-      Optional<ImmutableList<AttributePolicy>> split(AttributePolicy x) {
+		Optional<List<AttributePolicy>> split(AttributePolicy x) {
         if (x instanceof JoinedAttributePolicy) {
           return Optional.of(((JoinedAttributePolicy) x).policies);
         } else {
-          return Optional.absent();
+			return Optional.empty();
         }
       }