在Android Studio中导出具有Manifest属性的Jar文件？

Question

I am trying to run a jar from Android studio. After a long Workaround, the jar file run perfectly.

Now i need to export the jar file from the android studio. I got the Jar file from the build/libs folder.

But the problem is that the jar file shows a error.

no main manifest attribute, in "app.jar"

So i found this solution. Can't execute jar- file: "no main manifest attribute"

Then i read about MANIFEST.MF & added the mail class to that file.

jar {
    manifest.attributes(
            'Main-Class': "com.Remo.server.RemoServerApp"
    )
}

After adding those in my gradle. My MANIFEST.MF contains the MainClass.

But im still getting the same error? How can i solve this ?

Note: The objective is that I want to Export a Runnable Jar file from the project.

UPDATE:

After Adding the MainClass in MANIFEST.MF. I got stuck with the below error.

Exception in thread "main" java.lang.NoClassDefFoundError: com/Remo/protocol/RemoConnection
    at com.Remo.server.RemoServerApp.<init>(RemoServerApp.java:33)
    at com.Remo.server.RemoServerApp.main(RemoServerApp.java:97)
Caused by: java.lang.ClassNotFoundException: com.Remo.protocol.RemoConnection
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 2 more

MANIFEST.MF

Manifest-Version: 1.0
Main-Class: com.Remo.server.RemoServerApp

UPDATE 2

From your solution what i understood is that we need to copy the remoprotocol jar file to the remoserver.

remoserver project gradle file

apply plugin: 'java'

sourceSets {
    main {
        resources.srcDirs = ['src/main/resources']
    }
}

dependencies {
    compile project(':remoprotocol')
    compile files('libs/bluecove-2.1.1.jar')
}

jar {
    manifest.attributes(
            'Main-Class': "com.remo.server.remoServerApp"
    )
    manifest.attributes(
            'Class-Path': configurations.runtime.files.collect { it.getName() }.join(' '))
}

task copyRTDependenciesToLib(type: Copy) {
    into "$buildDir/output/lib"
    from configurations.runtime
}

After running the gradle task also i am getting the same error.

Answer 1

First you want to copy all your runtime dependencies into the builddir/libs folder (or a different distribution folder if you so choose). Here is a custom task that would achieve this:

task copyRTDependenciesToLib(type: Copy) {
    into "$buildDir/libs"
    from configurations.runtime
}

Add your runtime dependency jars as a Class-Path attribute in your manifest file. The jars need to be in the same directory as your runnable jar - which the copy task above achieves. (alternatively, you can provide full relative path for your dependency jar location)

jar {
    manifest {
        attributes(
           "Main-Class": "com.Remo.server.RemoServerApp",
           "Class-Path": configurations.runtime.files.collect { it.getName() }.join(' '))
         )
    }
}

Some more things to consider:

• The application plugin does the same thing; it adds a task installDist that produces a runnable set of jars along with any dependencies, any readme's, documentation you want to include.

• If you want to produce a single runnable jar without having to bundle dependencies along with it, you should look into creating a "fatjar", for example:

   task fatJar(type: Jar) { manifest { attributes 'Implementation-Title': 'Gradle Jar File Example', 'Implementation-Version': version, 'Main-Class': "com.Remo.server.RemoServerApp" } baseName = project.name //collect all dependencies from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } } with jar } 

Answer 2

I have no experience with Android Studio (or Gradle), but I have with Java. Aren't you trying to set main class instead?

Therefore I suggest changing Class-Path attribute to Main-Class as the manifest should contain Main-Class to be able to invoke something when "running" JAR.