What kind of constructor is this, beginning with <T extends Drawable & DrawerToggle>?
<pre><code>&lt;T extends Drawable &amp; DrawerToggle&gt; ActionBarDrawerToggle(
        Activity activity, 
        Toolbar toolbar,
        DrawerLayout drawerLayout, 
        T slider,
        @StringRes int openDrawerContentDescRes,
        @StringRes int closeDrawerContentDescRes) {
</code></pre>

<p>During browsing source code of the class <a href="http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/5.0.2_r1/android/support/v7/app/ActionBarDrawerToggle.java" rel="nofollow noreferrer">ActionBarDrawerToggle.java</a>, I've found this constructor is declared without access specifier. Rather, its declaration starts with</p>

<pre><code>&lt;T extends Drawable &amp; DrawerToggle&gt;
</code></pre>

<p>Please explain, what does it really mean?</p>