Erro com Classe no Java

public class MainActivity extends AppCompatActivity {

    private SectionsPagerAdapter mSectionsPagerAdapter;
    private ViewPager mViewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

        mViewPager = (ViewPager) findViewById(R.id.container);

        TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);

        TabItens tbiten = new TabItens(tabLayout,  mSectionsPagerAdapter);
        tbiten.AddTabItem("Fragment01", "Tab TST 01");
        tbiten.AddTabItemIco("Fragment02", "Tab 2", android.R.drawable.ic_dialog_email);
        tbiten.AddTabItem("Fragment03", "Tab 3 Item");
        tbiten.AddTabItemIco("Fragment04", "Tab 4", android.R.drawable.ic_dialog_dialer);
        tbiten.AddTabItemIco("Fragment01", "", android.R.drawable.ic_dialog_map);
        tbiten.AddTabItemIco("Fragment02", "Tab 6", android.R.drawable.ic_dialog_info);

        mViewPager.setAdapter(mSectionsPagerAdapter);

        tabLayout.setupWithViewPager(mViewPager);

        //mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        //tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager));

    }

    public static class TabItens {
        TabLayout tabLayout;
        SectionsPagerAdapter mSPAdapter
        String titulo;
        int resId;

        public TabItens(TabLayout tabLayout, SectionsPagerAdapter mSPAdapter) {
            this.tabLayout = tabLayout;
            this.mSPAdapter = mSPAdapter;
        }

        public void AddTabItem(String tabfragment, String titulo) {
            tabLayout.addTab(tabLayout.newTab().setText(titulo));
            mSPAdapter.addFragment(new tabfragment);
        }

        public void AddTabItemIco(String tabfragment, String titulo, int resId) {
            tabLayout.addTab(tabLayout.newTab().setIcon(resId).setText(titulo));
            mSPAdapter.addFragment(new tabfragment);
        }
    }



    public class SectionsPagerAdapter extends FragmentPagerAdapter {

        private final List<Fragment> mFragmentList = new ArrayList<>();

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        public void addFragment(Fragment fragment) {
            mFragmentList.add(fragment);
        }

        @Override
        public Fragment getItem(int position) {
            return mFragmentList.get(position);
        }

        @Override
        public int getCount() {
            return mFragmentList.size();
        }
    }
}