Using Style in Theme

<item name="android:windowTranslucentStatus">true</item>
<item name="android:windowTranslucentNavigation">true</item>

On activity layout add

android:fitsSystemWindows="true"

Using only Java

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
  Window w = getWindow(); // in Activity's onCreate() for instance
  w.setFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS, WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
}