Upstream uses URLDecoder.decode(String, Charset) - unavailable in Java 9

--- a/native/build.xml
+++ b/native/build.xml
@@ -1,7 +1,7 @@
 <project default="all" name="JPype - Native">
 
 	<!-- JAVA_VERSION must match the oldest supported Java version -->
-	<property name="JAVA_VERSION" value="9" />
+	<property name="JAVA_VERSION" value="11" />
 
 	<!-- src can't be "java" as it breaks nose tests -->
 	<property name="src" location="jpype_module/src/main/java"/>
@@ -17,16 +17,14 @@
 		<mkdir dir="${build}/classes/META-INF/versions/0"/>
 		<mkdir dir="${build}/lib"/>
 		<javac destdir="${build}/classes"
-			source="${JAVA_VERSION}"
-			target="${JAVA_VERSION}"
+			release="${JAVA_VERSION}"
 			excludes="**/Reflector0.java"
             includeantruntime="false"
 			>
 			<src path="${src}"/>
 		</javac>
 		<javac destdir="${build}/classes/META-INF/versions/0"
-			source="${JAVA_VERSION}"
-			target="${JAVA_VERSION}"
+			release="${JAVA_VERSION}"
 			includes="**/Reflector0.java"
             includeantruntime="false"
 			>