Error:
Exception in thread "LWJGL Application" java.lang.IllegalStateException: SpriteBatch.end must be called before begin.
    at com.badlogic.gdx.graphics.g2d.SpriteBatch.begin(SpriteBatch.java:167)
    at com.shootthefacedontdie.game.shotthefacedontdie.screen.game.com.MainMenu.render(MainMenu.java:35)
    at com.shootthefacedontdie.game.MainClass.render(MainClass.java:33)
    at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:225)
    at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126)

package com.shootthefacedontdie.game;

import com.badlogic.gdx.Game;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.g2d.BitmapFont;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.shootthefacedontdie.game.shotthefacedontdie.screen.game.com.GameScreen;
import com.shootthefacedontdie.game.shotthefacedontdie.screen.game.com.MainMenu;

public class MainClass extends Game {

    public SpriteBatch batch;
    public BitmapFont font;
    private GameScreen gameScreen;
    private MainMenu mainMenu;

    @Override
    public void create () {
        batch=new SpriteBatch();
        gameScreen=new GameScreen(this);
        mainMenu=new MainMenu(this);
        gameScreen.create();

    }

    @Override
    public void render()
    {
        batch.begin();
        Gdx.gl.glClearColor(0, 0, 0, 0);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
        mainMenu.render(60);
        gameScreen.render(60);
        batch.end();
    }

    @Override
    public void dispose ()
    {
        gameScreen.dispose();
        batch.dispose();
    }
}

package com.shootthefacedontdie.game.shotthefacedontdie.screen.game.com;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Screen;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.shootthefacedontdie.game.MainClass;

/**
 * Created by marcel on 29.01.17.
 */

public class MainMenu implements Screen{

    private final MainClass game;

    private OrthographicCamera camera;

    public MainMenu(final MainClass gam) {
        this.game = gam;

        camera = new OrthographicCamera();
        camera.setToOrtho(false, 800, 480);

    }

    @Override
    public void render(float delta) {
        Gdx.gl.glClearColor(0, 0, 0.2f, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

        camera.update();
        game.batch.setProjectionMatrix(camera.combined);

        game.batch.begin();
        game.font.draw(game.batch, "Welcome to MainClass!!! ", 100, 150);
        game.font.draw(game.batch, "Tap anywhere to begin!", 100, 100);
        game.batch.end();

        if (Gdx.input.isTouched()) {
            game.setScreen(new GameScreen(game));
            dispose();
        }

    }

    @Override
    public void show() {

    }

    @Override
    public void resize(int width, int height) {

    }

    @Override
    public void pause() {

    }

    @Override
    public void resume() {

    }

    @Override
    public void hide() {

    }

    @Override
    public void dispose() {

    }
}