Java env alpha (#656)

This change adds support for JVM based environment for running Java functions. This is alpha release of JVM environment and might undergo changes.

examples/jvm/java/.gitignore

@@ -0,0 +1,4 @@
+.project
+.settings
+.classpath
+target/

examples/jvm/java/build.sh

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+#!/bin/sh
+# This script allows you to build the jar without needing Maven & JDK installed locally. 
+# You need docker, as it uses a Docker image to build source code
+
+docker run -it --rm  -v "$(pwd)":/usr/src/mymaven -w /usr/src/mymaven maven:3.5-jdk-8 mvn clean package

examples/jvm/java/pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>io.fission</groupId>
+	<artifactId>hello-world</artifactId>
+	<version>1.0-SNAPSHOT</version>
+	<packaging>jar</packaging>
+
+	<name>hello-world</name>
+	<url>http://maven.apache.org</url>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+	</properties>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+			<version>2.0.1.RELEASE</version>
+			<scope>provided</scope>
+		</dependency>
+		<dependency>
+			<groupId>io.fission</groupId>
+			<artifactId>fission-java-core</artifactId>
+			<version>0.0.2-SNAPSHOT</version>
+			<scope>provided</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<artifactId>maven-assembly-plugin</artifactId>
+				<configuration>
+					<descriptorRefs>
+						<descriptorRef>jar-with-dependencies</descriptorRef>
+					</descriptorRefs>
+				</configuration>
+				<executions>
+					<execution>
+						<id>make-assembly</id> <!-- this is used for inheritance merges -->
+						<phase>package</phase> <!-- bind to the packaging phase -->
+						<goals>
+							<goal>single</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+
+	<!-- Adding Sonatype repository to pull snapshots -->
+	<repositories>
+		<repository>
+			<id>fission-java-core</id>
+			<name>fission-java-core-snapshot</name>
+			<url>https://oss.sonatype.org/content/repositories/snapshots/</url>
+		</repository>
+	</repositories>
+
+</project>

examples/jvm/java/src/main/java/io/fission/HelloWorld.java

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+package io.fission;
+
+import org.springframework.http.RequestEntity;
+import org.springframework.http.ResponseEntity;
+
+import io.fission.Function;
+import io.fission.Context;
+
+public class HelloWorld implements Function {
+
+	@Override
+	public ResponseEntity<?> call(RequestEntity req, Context context) {
+		return ResponseEntity.ok("Hello World!");
+	}
+
+}

examples/jvm/java/src/test/java/io/fission/HelloWorldTest.java

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+package io.fission;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.RequestEntity;
+import org.springframework.http.ResponseEntity;
+import org.springframework.util.Assert;
+
+public class HelloWorldTest {
+
+	public void testResponse() {
+		HelloWorld hw = new HelloWorld();
+		RequestEntity request = null;
+		try {
+			request = RequestEntity.get(new URI("http://example.com/bar")).build();
+		} catch (URISyntaxException e) {
+			e.printStackTrace();
+		}
+		ResponseEntity resp = hw.call(request, null);
+		Assert.hasText(resp.getBody().toString(), "Hello World!");
+	}
+}