resources folder in .jar file? (java.io.FileNotFoundException)

[renlite]

I'm trying littleKt and use Maven as build tool. For "copy-resources" I tried as outputDir:

<outputDirectory>${project.build.outputDirectory}</outputDirectory>
<outputDirectory>${project.build.outputDirectory}/resources</outputDirectory>

and get

VfsFile(vfs=com.littlekt.file.JvmVfs@3f1d2e23, path=)
VfsFile(vfs=com.littlekt.file.JvmVfs@3f1d2e23, path=.)
.
PathInfo(fullPath=.)
[09:15:47.504] - [Thread: 24] - [Tiled Map 001]: Failed loading asset ./tiled/ortho-tiled-world.tmj: java.io.FileNotFoundException: .\tiled\ortho-tiled-world.tmj

What is the correct (root) path in the target .jar (File) for resources?

[LeHaine]

Hey! I am not too knowledgeable on Maven but I can tell you that the resourcesVfs relies on the working directory that the JAR is run. If you package the resources inside the JAR, as a fat JAR, it should automatically find it. If the resources are separate, then it will need to use a path based on the running directory of the JAR.

[renlite]

Hi, thanks for your reply. Yes it's inside a self-contained JAR. I tested it in the (root) "/" and in the "/resources" of the JAR.

"/tiled/..."
"/resources/tiled/..."

[renlite]

I found this:
https://stackoverflow.com/questions/8258244/accessing-a-file-inside-a-jar-file/8258308#8258308
How does littleKt read the files? With the "File class" or as an "InputStream (getResourceAsStream())"? File class seems not to work in a fat JAR.

[LeHaine]

For the JVM, it'll attempt to create an InputStream from the from ClassLoader.getSystemResourceAsStream(). If it doesn't succeed, it'll create one using a plain old FileInputStream.

[renlite]

I think it's the leading "./" littleKt inserts to the asset(path). See exception above:

fun main() {
    val path = "tiled/ortho-tiled-world.tmj"
    var inStream = ClassLoader.getSystemResourceAsStream(path)
    if (inStream == null) {
        println("ISSUE: $path")
    } else {
        println("OK: $path")
    }
}

// output:
// OK: tiled/ortho-tiled-world.tmj
// ISSUE: /tiled/ortho-tiled-world.tmj
// ISSUE: ./tiled/ortho-tiled-world.tmj

[LeHaine]

Nice catch. That makes sense. Each Vfs allows setting of a baseDir with defaults to ".". Unfortunately, there isn't a way to exclude the base directory, currently, without a fix as the asset gets a / prepended to the path. Vfs should probably have the baseDir as optional. And really, there should be a few Vfs types instead of a resourcesVfs which loads externally as well. resourcesVfs for internal JAR resources, fileVfs for external files, etc.

[LeHaine]

@renlite this should now be fixed in #276. I tested with fat JARs, built via gradle, which loaded from it fine.

[renlite]

Thank you! Will you publish the new version to maven repository?

[LeHaine]

The snapshot version is available currently on maven: 0.10.2.24c32b7-SNAPSHOT. A new release will go out I just want to bundle a few more things.

[renlite]

I searched for snapshots of littleKt but can't find any. In which repository is it deployed? (Maven Central?)

<dependency>
            <groupId>com.littlekt</groupId>
            <artifactId>core-jvm</artifactId>
            <version>0.10.2.24c32b7-SNAPSHOT</version>
</dependency>

[renlite]

I'm not an expert in JVM and Maven: This is my config "pom.xml" to try it with littleKt. I have also tried "Amper Standalone" but at the moment (Version 0.4) there seems not to be a way to pass args (--enable-preview) to the JVM.

<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>com.mycompany.tiled</groupId>
    <artifactId>MyGame</artifactId>
    <version>1.0</version>

    <properties>
        <kotlin.version>2.0.10</kotlin.version>
        <kotlin.compiler.jvmTarget>21</kotlin.compiler.jvmTarget>
        <kotlin.compiler.incremental>true</kotlin.compiler.incremental>
        <main.class>my/game/TiledKt</main.class>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-stdlib</artifactId>
            <version>${kotlin.version}</version>
        </dependency>
        <dependency>
            <groupId>com.littlekt</groupId>
            <artifactId>core-jvm</artifactId>
            <version>0.10.1</version>
        </dependency>
    </dependencies>



    <build>
        <sourceDirectory>${project.basedir}/src</sourceDirectory>
        <testSourceDirectory>${project.basedir}/src</testSourceDirectory>

        <plugins>

            <plugin>
                <groupId>org.jetbrains.kotlin</groupId>
                <artifactId>kotlin-maven-plugin</artifactId>
                <version>${kotlin.version}</version>

                <executions>
                    <execution>
                        <id>compile</id>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                    </execution>

                    <execution>
                        <id>test-compile</id>
                        <goals>
                            <goal>test-compile</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>3.4.1</version>
                <executions>
                  <execution>
                    <goals>
                      <goal>java</goal>
                    </goals>
                  </execution>
                </executions>
                <configuration>
                  <mainClass>my.game.TiledKt</mainClass>
                  <arguments>

                  </arguments>
                  <systemProperties>

                  </systemProperties>
                </configuration>
            </plugin>

            <plugin>
                <artifactId>maven-resources-plugin</artifactId>
                <version>3.3.1</version>
                <executions>
                  <execution>
                    <id>copy-resources</id>

                    <phase>validate</phase>
                    <goals>
                      <goal>copy-resources</goal>
                    </goals>
                    <configuration>
                      <outputDirectory>${project.build.outputDirectory}</outputDirectory>
                      <resources>          
                        <resource>
                          <directory>${project.basedir}/resources</directory>
                        </resource>
                      </resources>              
                    </configuration>            
                  </execution>
                </executions>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.6</version>
                <configuration>
                    <archive>
                        <manifest>
                            <addClasspath>true</addClasspath>
                            <mainClass>${main.class}</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-assembly-plugin</artifactId>
                <version>2.6</version>
                <executions>
                    <execution>
                        <id>make-assembly</id>
                        <phase>package</phase>
                        <goals> <goal>single</goal> </goals>
                        <configuration>
                            <archive>
                                <manifest>
                                    <mainClass>${main.class}</mainClass>
                                </manifest>
                            </archive>
                            <descriptorRefs>
                                <descriptorRef>jar-with-dependencies</descriptorRef>
                            </descriptorRefs>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
        
    </build>

</project>

[LeHaine]

Maybe something like this from my quick research:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-compiler-plugin</artifactId>
  <configuration>
    <source>21>
    <target>21</target>
    <compilerArgs>--enable-preview</compilerArgs>
  </configuration>
</plugin>

[renlite]

No good explenation from me. With Maven it works because I can start the JAR with Java command. What I mean is to switch to Amper as soon the build tool can pass args to the JVM or can create a fat JAR file.