Eclipse - How to add Kotlin to a Tomcat Project - Compile Kotlin AND Java Files - eclipse

Question

I need help adding Kotlin compiling to an existing eclipse java tomcat project.
For the record I am on Eclipse Oxygen 4.7, and have installed the Kotlin plugin. I have successfully created and ran gradle based spring boot Kotlin rest api demo and can compile and run "Kotlin Only Projects" and use my other java libs - AWESOME.
However now that I have Kotlin I want to use it in work for my other 'legacy' Tomcat 8 projects that are Java J2EE - Dynamic WTP ... new servlets I want to write in Kotlin.
I want to be able to add a Kotlin class in the java src folder in any of my previous packages so when I build a war it all logically together.
The IDE seems ok with this - I created a Kotlin class in a package (in a tomcat project java src package folder) and it have no issues on resolving, imports, or dependency...
I was thinking WOW!, Ok now to restart the Tomcat server in WTP and I'll be able to execute my Kotlin Servlet. No - 404 404 404.
I inspected the WEB-INF/classes build folder and along all the Java class files... guess what I saw?! A file called KotlinServlet.kt ( thats the name of my test servlet, the source version not a compile class version)
So for some reason the build /package/ deployment did not bother to compile the *.kt file and just copied it over (maybe that is the default for general WTP deploy).
I wonder if this would be solved by "Add Kotlin Nature" , the strange part is that none of the eclipse Kotlin menu functions are available to me. If I right click my project I get no Kotlin menu options.
Eclipse states the plugin is installed.
So my question is:
Given an existing conventional WTP Tomcat servlet project, HOW can we get it to identify and a compile *.kt files? How and why do I not have the Kotlin menu functions? (I downloaded and tested both the Oxygen Java and J2EE version - installed the Kotlin plugin - and no menus there either to add a Kotlin Nature. I also then tried the nightly build of the plugin. No menus appeared. Obviously the puglin is installed compiling other Kotlin projects and works in the editor.
From my research - "Add Kotlin Nature" is supposed to do the trick for joint Java / Kotlin compiling but that menu function is not available anywhere???
If this is a "Kotlin Project" eclipse compiles Kotlin fine.
Any Ideas? Seems like an IntelliJ conspiracy.
Thanks,

Answer 1

You need add correspond dependencies. The easiest way to manage project dependencies is to use build tools (maven, gradle, Ant+Ivy...). In maven example you need:
<properties>
<!-- your properties... and define version fir kotlin -->
<kotlin.version>1.1.4</kotlin.version>
</properties>
<dependencies>
<!-- your project dependencies... and add one for kotlin -->
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-stdlib-jre8</artifactId>
<version>${kotlin.version}</version>
</dependency>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-test</artifactId>
<version>${kotlin.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<!-- your project plugins... and add one for kotlin -->
<plugin>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-maven-plugin</artifactId>
<version>${kotlin.version}</version>
<executions>
<execution>
<id>compile</id>
<phase>compile</phase>
<goals>
<goal>compile</goal>
</goals>
</execution>
<execution>
<id>test-compile</id>
<phase>test-compile</phase>
<goals>
<goal>test-compile</goal>
</goals>
</execution>
</executions>
<configuration>
<jvmTarget>1.8</jvmTarget>
</configuration>
</plugin>
</plugins>
</build>
If you use IDE you need to install kotlin language support plugin to make kotlin compile or test run more user friendly.

Answer 2

OK I am narrowing in on this. I found that the kotlin classes are being compiled to this location under runtime lib? Maybe this will be something I can figure to build to my normal classes folder.

Answer 3

OK - To get all the Kotlin menus - turns out you need to be on PACKAGE EXPLORER tab not PROJECT EXPLORER . arggh just found that by fluke.
The creation of a .kt file will automatically add the runtime and libs for Kotlin to your project.
Now on the the issue of the build / compile now. Still outstanding.

Answer 4

OK Update - Downloaded IntelliJ, and "IT" works out of the box, in 15 min I had a Hybrid Java/Kotlin Tomcat Project running.
Still Interested in the Eclipse solution but I am probably just going to shell out the cash for IntelliJ. Time is money.