I'm Beginner in Java, I have a error message with .gradle and Soursets with main. How can I solve this problem? : I'm beginner in Java and Android-Studio.
From the first step, i got a big problem. 
When I typed my first Java code in And-Stu and I ran the code, but I got this error message...
---------------------------------------------------------
FAILURE: Build failed with an exception.

* Where:
Initialization script 'C:\Users\forma\AppData\Local\Temp\asdb_main__.gradle' line: 20

* What went wrong:
A problem occurred configuring project ':app'.
> Could not create task ':app:asdb.main()'.
   > SourceSet with name 'main' not found.
---------------------------------------------------------

So, I looked for the .gradle file, but I don't know what the problem is.

How can I solve this problem?
    

i ran this code but i got the error message.

    package com.example.myapplication;

    public class asdb {
        public static void main(String[] args) {
            int a;
            a=10;
            System.out.println(a);
        }
    }




and this is .gralde code including line 20.

    def gradlePath = ':app'
    def runAppTaskName = 'asdb.main()'
    def mainClass = 'com.example.myapplication.asdb'
    def javaExePath = 'C:/Program Files/Android/Android Studio/jre/bin/java.exe'
    def _workingDir = 'C:/Users/forma/Desktop/practice/java2'

    def sourceSetName = 'main'
    def javaModuleName = null

    

    allprojects {
      afterEvaluate { project ->
        if(project.path == gradlePath && project?.convention?.findPlugin(JavaPluginConvention)) {
          project.tasks.create(name: runAppTaskName, overwrite: true, type: JavaExec) {
            if (javaExePath) executable = javaExePath
            classpath = project.sourceSets[sourceSetName].runtimeClasspath
            main = mainClass