Getting exception while creating and reading file

shuhabazhar · May 10, 2024, 10:27am

Hello MicroEJ team,

I’m trying to store a file in the simulator, I am using the MicroEJ version.

and below is a code from the foundation library that I am using and using the same configuration defined in the example below.

github.com

MicroEJ/Example-Foundation-Libraries/blob/master/fs.helloworld/src/main/java/com/microej/example/foundation/fs/helloworld/ExampleFileSystem.java

/*
 * Copyright 2014-2020 MicroEJ Corp. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be found with this software.
 */
package com.microej.example.foundation.fs.helloworld;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Date;

/**
 * <p>Demonstrates some usage of file system actions such as directory creation,
 * file creation, file content writing, file deletion, ...</p>
 */
public class ExampleFileSystem {

	/**
	 * <p>

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From this, I am getting the below exception:

Uncaught exception thrown in Feature demoapp (CN=com.is2t.feature.demoapp, OU=IS2T, O=IS2T, L=NANTES, ST=FRANCE, C=FR):
Exception in thread “com.is2t.feature.demoapp” java.lang.RuntimeException
at java.lang.Throwable.fillInStackTrace(Throwable.java:82)
at java.lang.Throwable.(Throwable.java:32)
at java.lang.Exception.(Exception.java:14)
at java.lang.RuntimeException.(RuntimeException.java:14)
at java.io.File.(File.java:154)
at com.medtronic.neuro.LandingPage.main(LandingPage.java:36)
at com.medtronic.neuro.LandingPage.start(LandingPage.java:260)
at ej.kf.Kernel$2.run(Kernel.java:237)
at java.lang.Thread.run(Thread.java:325)
at java.lang.Thread.runWrapper(Thread.java:387)

Could you please help me with this issue?

rlouedec · May 16, 2024, 9:01pm

Hi Shuhabazhar,

Sorry for the delay…

It seems that the issue is that you are running against the FS API.
This “FS API” module is only meant for compilation and this dependency is normally replaced at build time by the implementation provided by the VEE Port / Kernel.

Let’s understand why it is not replaced.
It seems you are running a Sandboxed Application (a “feature”).
What Kernel are you using ? For your Application to access the File System Foundation Library API, the Kernel must have it in its Runtime API.
https://docs.microej.com/en/latest/KernelDeveloperGuide/kernelAPI.html

Also, can you clarify which MICROEJ SDK version you are using ? SDK 5 (MMM / Eclipse) ? SDK 6 (Gradle) ?

Best regards,
Rémy

shuhabazhar · May 21, 2024, 1:48pm

Hi @rlouedec,
I am using ej.api:fs:2.1.1 in build.gradle file and manually added the fs-2.1.1 jar file in the following locations.

…\demoapp\app\build\vee\javaLibs
…\demoapp\app\build\vee\MICROJVM\javaLibs
and I am using MICROEJ SDK 6.

Thanks

rlouedec · May 21, 2024, 3:42pm

Hi @shuhabazhar,

Ok, I understand now why you have the issue at runtime instead of an error at buildtime.
The javaLibs folder is for libraries implementations packaged with VEE Ports.
In your case, you added the API jar of the File System foundation library. This jar does not contain any implementation and should be used for compilation only.

Different VEE Ports may provide different implementations (versions) of the same Foundation Library API.
So applications can depend on the same API Jar, but build against different VEE Ports for different targets using different implementations/versions of the same FS API Jar.
See Libraries — MicroEJ Documentation

What you need to do in your case is to add the FS Pack to your VEE Port.
For that, you can add our FS Pack available publicly on the MicroEJ Central Repository.

In yyy-configuration/module.ivy, add:

	<dependencies>
		<!-- ... -->
		<dependency org="com.microej.pack" name="fs" rev="6.0.4"/>
		<!-- ... -->
	</dependencies>

and in yyy-configuration/yyy.platform, add:

    <group name="fs"/>

See also: File System — MicroEJ Documentation

Best regards,
Rémy