关于错误“线程“ main”中的异常”的问题java.lang.NoSuchMethodError：io.netty.resolver.HostsFileParser.parseSilently（）Ljava / util / Map;”

Question

import io.vertx.core.AbstractVerticle;
import io.vertx.core.Vertx;
import io.vertx.ext.web.Router;
public class app extends AbstractVerticle{
    @Override
    public void start() throws Exception{
        Router router = Router.router(vertx);
        router.route().handler(routingContext -> {
            routingContext.response()
            .putHeader("content-type", "text/html")
            .end("hello vert.x");
        });
        vertx.createHttpServer().requestHandler(router::accept).listen(8888);
    }
    public static void main(String[] args) {
        Vertx vertx = Vertx.vertx();
        vertx.deployVerticle(new app());
    }
}

then error occurs as java.lang.NoSuchMethodError: io.netty.resolver.HostsFileParser.parseSilently()Ljava/util/Map;

Answer 1

Try this way

import io.vertx.core.AbstractVerticle;
import io.vertx.ext.web.Router;

public class Server extends AbstractVerticle {

  @Override
  public void start() throws Exception {

    Router router = Router.router(vertx);

    router.route().handler(routingContext -> {
      routingContext.response().putHeader("content-type", "text/html").end("hello vert.x");
    });

    vertx.createHttpServer().requestHandler(router::accept).listen(8080);
  }
}

run mvn clean package then java -jar /path/to/jar

Also in java app is not a valid class name. Class names start with a capital eg App