lingdx button test

package com.marsminer.game;

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Game;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.assets.AssetManager;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.Batch;
import com.badlogic.gdx.graphics.g2d.BitmapFont;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.graphics.g2d.TextureAtlas;
import com.badlogic.gdx.scenes.scene2d.Stage;
import com.badlogic.gdx.scenes.scene2d.ui.Skin;
import com.badlogic.gdx.scenes.scene2d.ui.TextButton;

import java.awt.Color;

import sun.applet.Main;

public class MarsMiner extends Game {
    Stage stage;
    TextButton button;
    TextButton.TextButtonStyle textButtonStyle;
    BitmapFont font;
    Skin skin;
    TextureAtlas textureAtlas;

    @Override
    public void create () {
        stage = new Stage();
        Gdx.input.setInputProcessor(stage);
        font = new BitmapFont();
        skin = new Skin();
        textureAtlas = new TextureAtlas(Gdx.files.internal("buttons/buttons.pack"));
        skin.addRegions(textureAtlas);
        textButtonStyle = new TextButton.TextButtonStyle();
        textButtonStyle.font = font;
        textButtonStyle.up = skin.getDrawable("up-button");
        textButtonStyle.down = skin.getDrawable("down-button");
        textButtonStyle.checked = skin.getDrawable("checked-button");
        button = new TextButton("Button1", textButtonStyle);
        stage.addActor(button);

    }

    @Override
    public void render () {
        Gdx.gl.glClearColor(1, 0, 0, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
        super.render();
        stage.draw();
    }
}

Output:

package com.marsminer.game;

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Game;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.assets.AssetManager;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.Batch;
import com.badlogic.gdx.graphics.g2d.BitmapFont;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.graphics.g2d.TextureAtlas;
import com.badlogic.gdx.scenes.scene2d.Stage;
import com.badlogic.gdx.scenes.scene2d.ui.Skin;
import com.badlogic.gdx.scenes.scene2d.ui.TextButton;

import java.awt.Color;

import sun.applet.Main;

public class MarsMiner extends Game {
    Stage stage;
    TextButton button;
    TextButton.TextButtonStyle textButtonStyle;
    BitmapFont font;
    Skin skin;
    TextureAtlas textureAtlas;

    @Override
    public void create () {
        stage = new Stage();
        Gdx.input.setInputProcessor(stage);
        font = new BitmapFont();
        skin = new Skin();
        textureAtlas = new TextureAtlas(Gdx.files.internal("buttons/buttons.pack"));
        skin.addRegions(textureAtlas);
        textButtonStyle = new TextButton.TextButtonStyle();
        textButtonStyle.font = font;
        textButtonStyle.up = skin.getDrawable("up-button");
        textButtonStyle.down = skin.getDrawable("down-button");
        textButtonStyle.checked = skin.getDrawable("checked-button");
        button = new TextButton("Button1", textButtonStyle);
        stage.addActor(button);

    }

    @Override
    public void render () {
        Gdx.gl.glClearColor(1, 0, 0, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
        super.render();
        stage.draw();
    }
}

Output:

Exception in thread "LWJGL Application" com.badlogic.gdx.utils.GdxRuntimeException: File not found: buttons\buttons.pack (Internal)
    at com.badlogic.gdx.files.FileHandle.read(FileHandle.java:136)
    at com.badlogic.gdx.graphics.g2d.TextureAtlas$TextureAtlasData.<init>(TextureAtlas.java:103)
    at com.badlogic.gdx.graphics.g2d.TextureAtlas.<init>(TextureAtlas.java:231)
    at com.badlogic.gdx.graphics.g2d.TextureAtlas.<init>(TextureAtlas.java:226)
    at com.badlogic.gdx.graphics.g2d.TextureAtlas.<init>(TextureAtlas.java:216)
    at com.marsminer.game.MarsMiner.create(MarsMiner.java:35)
    at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:149)
    at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126)