Why does the application crash when connecting Toolbar to MainActivity?

Question

Web development

Now minSdkVersion 19, as I understand it, it did not pull the Toolbar. When I connect the Toolbar to MainActivity, the application crashes when I start it, if I comment it out, then everything starts. Tell me what can be done so that with the same minimum version of the SDK, the Toolbar would work for me.

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

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            toolbar = (Toolbar)findViewById(R.id.main_toolbar);
        }
        // setSupportActionBar(toolbar);
      //  getSupportActionBar().setTitle("Chatden");

        viewPager = (ViewPager) findViewById(R.id.main_tabs_pager);
        tabsAccessorAdapter = new TabsAccessorAdapter(getSupportFragmentManager());
        viewPager.setAdapter(tabsAccessorAdapter);

        tabLayout = (TabLayout) findViewById(R.id.mainTabLayout);
        tabLayout.setupWithViewPager(viewPager);

    }

Here are the logs

11-13 11:19:58.057 16347-16347/com.example.chatden E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.chatden, PID: 16347
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.chatden/com.example.chatden.MainActivity}: java.lang.ClassCastException: androidx.appcompat.widget.Toolbar cannot be cast to android.widget.Toolbar
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2511)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2571)
        at android.app.ActivityThread.access$900(ActivityThread.java:165)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1409)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:171)
        at android.app.ActivityThread.main(ActivityThread.java:5620)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:732)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:622)
     Caused by: java.lang.ClassCastException: androidx.appcompat.widget.Toolbar cannot be cast to android.widget.Toolbar
        at com.example.chatden.MainActivity.onCreate(MainActivity.java:35)
        at android.app.Activity.performCreate(Activity.java:6320)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1121)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2464)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2571) 
        at android.app.ActivityThread.access$900(ActivityThread.java:165) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1409) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:171) 
        at android.app.ActivityThread.main(ActivityThread.java:5620) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:732) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:622) 

Answer 1

That's why. Imports need to be fixed.