NullPointerException in server (scala)

Main.scala:

package chicken    import java.io.IOException  import java.net.{ServerSocket, Socket}    class Main(c:Socket) extends Runnable{      def main(args: Array[String]): Unit = {      try {        var sSocket:ServerSocket = new ServerSocket(ServerUtility.PORT)          while (true) {          var server:Main = new Main(sSocket.accept())            var cThread:Thread = new Thread(server)          cThread.start()        }      }catch {        case e: IOException => println("ERROR FOUND: " + e.getStackTrace() + "!")        case e: NullPointerException => println("NULL POINTER FOUND: " + e.getStackTrace() + "!")      }    }      override def run(): Unit = {      }  }  

Utils.scala

package chicken    object Utils {      val PORT:Int = 8888    }  

I get a NullPointerException error but the scala cmd for windows doesnt tell me where it is and when I use java to run it, it just says: no main manifest attribute, in Server.jar

I have no idea where it could be since I have also tried and catch the server sockets and threads.

The error message is:

java.lang.NullPointerException          at java.lang.Class.forName0(Native Method)          at java.lang.Class.forName(Unknown Source)          at scala.reflect.internal.util.ScalaClassLoader.$anonfun$tryClass$1(ScalaClassLoader.scala:52)          at scala.util.control.Exception$Catch.$anonfun$opt$1(Exception.scala:246)          at scala.util.control.Exception$Catch.apply(Exception.scala:228)          at scala.util.control.Exception$Catch.opt(Exception.scala:246)          at scala.reflect.internal.util.ScalaClassLoader.tryClass(ScalaClassLoader.scala:52)          at scala.reflect.internal.util.ScalaClassLoader.tryToInitializeClass(ScalaClassLoader.scala:48)          at scala.reflect.internal.util.ScalaClassLoader.tryToInitializeClass$(ScalaClassLoader.scala:48)          at scala.reflect.internal.util.ScalaClassLoader$URLClassLoader.tryToInitializeClass(ScalaClassLoader.scala:132)          at scala.reflect.internal.util.ScalaClassLoader.run(ScalaClassLoader.scala:99)          at scala.reflect.internal.util.ScalaClassLoader.run$(ScalaClassLoader.scala:98)          at scala.reflect.internal.util.ScalaClassLoader$URLClassLoader.run(ScalaClassLoader.scala:132)          at scala.tools.nsc.CommonRunner.run(ObjectRunner.scala:28)          at scala.tools.nsc.CommonRunner.run$(ObjectRunner.scala:27)          at scala.tools.nsc.JarRunner$.run(MainGenericRunner.scala:21)          at scala.tools.nsc.CommonRunner.runAndCatch(ObjectRunner.scala:35)          at scala.tools.nsc.CommonRunner.runAndCatch$(ObjectRunner.scala:34)          at scala.tools.nsc.JarRunner$.runAndCatch(MainGenericRunner.scala:21)          at scala.tools.nsc.JarRunner$.runJar(MainGenericRunner.scala:33)          at scala.tools.nsc.MainGenericRunner.runTarget$1(MainGenericRunner.scala:79)          at scala.tools.nsc.MainGenericRunner.run$1(MainGenericRunner.scala:92)          at scala.tools.nsc.MainGenericRunner.process(MainGenericRunner.scala:103)          at scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:108)          at scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala)  

Scalac to build, Scala to run (windows command prompt commands)

https://stackoverflow.com/questions/65545854/nullpointerexception-in-server-scala January 03, 2021 at 09:31AM