NewJavaToKotlinConverter.filesToKotlin giving "java.lang.IllegalStateException: Calling invokeAndWait from read-action leads to possible deadlock."

I am trying to run IntelliJ J2K from command line. Since there is no way of running this tool from command line, I am using the following hack.
 
1. Since code inspections can be run from command line, I am trying to wrap J2K conversion logic inside code inspection. (Something similar to this. But this inspection tool is not useful since it only works until first phase conversion).
2. I found out the conversion is a two step process, a. First phase Java to Kotlin Conversion b. Post processing the converted Kotlin. 
a. If I use elementsToKotlin method, it works fine for first the first step. But the converted Kotlin is still not clean.

For example, following JAVA code gets converted to,

package demo;

public class Demo {
    private String name="kiran";
}

this,

package demo class Demo constructor (){ private var name:/*@@adhquo@@*/kotlin.String? = "kiran" } 

Here, as you can see, the converted code is verbose with unnecessary `constructor()` etc. The code is also not formatted. 

b. There is another method filesToKotlin that does first phase conversion and post processing as well. However, I found that it is doing the first phase well, but when going through second phase(post processing), it is failing with below error. 

`"java.lang.IllegalStateException: Calling invokeAndWait from read-action leads to possible deadlock."`

Here, is the code snippet. 

val extension = NewJ2kConverterExtension()
val newJavaToKotlinConverter = extension.createJavaToKotlinConverter(project, module, defaultSettings, oldServices)
try {
   val filesResult = newJavaToKotlinConverter.filesToKotlin(javaFileList,extension.createPostProcessor(true))
} catch (e:Exception) {
   e.printStackTrace()
}

The reason for this is, as part of post processing, and to rename the `.java` file to `.kt` file, the `NewJavaToKotlinConverter` class is using this method to dispatch a task to the event thread of IDE. The invokeAndWait method is used to execute a task on the IntelliJ IDEA event dispatch thread and it is throwing this error maybe because it is a blocking operation. There is another method called invokeLater for Application class but none of the `NewJavaToKotlinConverter` methods are using it. 

Can you please tell me how to fix this error?