Authors: JanHolger, Digital

• Create JVMs.
• Communicate from Lua <-> Java.

Check out Releases for a download to Windows & Linux builds.

If you have the following error in console while loading our Java plugin,

[2019-12-27 20:01:37] [info] Loading plugin "OnsetJavaPlugin"
[2019-12-27 20:01:37] [error] Failed loading "OnsetJavaPlugin": The specified module could not be found.

This is typically an issue with Windows users. To fix this, add your Java 8 bin/server folder to your PATH configuration. Example of JDK (or JRE) path: C:\Program Files\Java\jdk1.8.0_221\jre\bin\server Make sure your Java installation is 64 bit otherwise it won't have the required JNI libraries we use.

• Lua String -> String (java.lang.String)
• Lua Int -> Integer (java.lang.Integer)
• Lua Bool -> Boolean (java.lang.Boolean)
• Lua Table -> Map (java.util.HashMap)

• String (java.lang.String)
• Integer (java.lang.Integer)
• Boolean (java.lang.Boolean)
• List (java.util.List)
• Map (java.util.Map)

We will be adding more data types later on.

Create a new JVM with a jar. Returns JVM ID.

local jvmID = CreateJava(path)

• path Relative path to the jar file, relative from the root server directory. Example: path/to/file.jar

Destroy a JVM.

DestroyJava(jvmID)

• jvmID ID to the JVM you have created using CreateJava.

Call a java static method. Can return information from the Java method, check out Data Types for the types we currently support.

local dataFromJava = CallJavaStaticMethod(jvmID, className, methodName, methodSignature, args...)

• jvmID ID to the JVM you have created using CreateJava. Example: 1
• className Class name of the class you want to call a method in, must include package path as well. Example: dev/joseph/Test (dev.joseph.Test).
• methodName Static method name you want to call. Example: returnTestInt
• methodSignature Signature of the method you want to call. Example: (Ljava/lang/Integer;)I
• args (Optional) Pass arguments into the method.

Links a Java class so the native methods below can be used.

LinkJavaAdapter(jvmID, className)

• jvmID ID to the JVM you have created using CreateJava. Example: 1
• className Class name of the class you want to call a method in, must include package path as well. Example: dev/joseph/Adapter (dev.joseph.Adapter).

Call Lua events from Java.

public class Adapter {
    public native static void callEvent(String event, List<Object> args);
}

Example:

Adapter.callEvent("testCallEvent", Arrays.asList("lol", "haha", "yeah"));
Adapter.callEvent("testCallEvent", Arrays.asList(1, 2, "hi", 384, "yeeep", true, false));

function testCallEvent(arg1)
  print ('first arg is ' .. arg1)
end
AddEvent('testCallEvent', testCallEvent)