title: Why non UI thread can modify UI?
body: <p>Yes, it shouldn't but the thread i made in my <code>mainActivity</code> in <code>onCreate</code> can modify UI, like this : </p>
  
  <pre><code>Thread thread = new Thread(new Runnable() {
              @Override
              public void run() {
                  someTextview.setText("Hello");
              }
          });
          thread.start();
  </code></pre>
  
  <p>I'm using android studio 2.2.2 .</p>