XML : Android 6.0 (Marshmallow) Denying permissions and no Permission Request Dialog is shown to user

After reading the Android docs, I decided to have a play around and "read sms messages from my device."

However, after setting permissions in Manifest, and writing code to request permissions in code behind (java), and after setting a breakpoint on RequestPermission(), I can see that my app crashes because "Permission denied."

Why am I getting permission denied when I have declared everything the docs have told me to declare and have also implemented that thing where you get the OS to ask the user to grant or deny permission (which doesn't even happen - it doesn't present me with a dialog to grant or deny permissions - my app just crashes before it even shows up!)

How can I figure out what's going on? How can I ask the user for permission for [specifically] READ_SMS permission?

Note that I have been bashing my head against the desk while trying to fix this for days, so the code here is the latest code I have, however there have been about 20 (complete) re-writes. So if something is missing, it may have already been there but was removed because it didn't work, or was removed in order to troubleshoot to see what works what doesn't.

Manifest:

  <?xml version="1.0" encoding="utf-8"?>  <manifest xmlns:android="http://schemas.android.com/apk/res/android"      package="com.me.app">        <application          android:allowBackup="true"          android:icon="@mipmap/ic_launcher"          android:label="@string/app_name"          android:supportsRtl="true"          android:theme="@style/AppTheme">            <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />          <uses-permission android:name="android.permission.READ_PHONE_STATE" />          <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />          <uses-permission android:name="android.permission.READ_SMS" />          <uses-permission android:name="android.permission.RECEIVE_SMS" />          <uses-feature              android:name="android.hardware.telephony"              android:required="true">          </uses-feature>          <grant-uri-permission android:path="content://sms/"              android:pathPattern=".*"              android:pathPrefix="\"/>          <activity              android:name=".Main"              android:label="@string/app_name"              android:theme="@style/AppTheme.NoActionBar">              <intent-filter>                  <action android:name="android.intent.action.MAIN" />                    <category android:name="android.intent.category.LAUNCHER" />              </intent-filter>          </activity>      </application>    </manifest>    

Main.java (onCreate(...)):

  @Override  protected void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      setContentView(R.layout.main);      Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);      setSupportActionBar(toolbar);        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);      fab.setOnClickListener(new View.OnClickListener() {          @Override          public void onClick(View view) {              Snackbar.make(view, "Testing Snackbar", Snackbar.LENGTH_LONG)                      .setAction("Action", null).show();          }      });        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);      ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(              this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);      drawer.setDrawerListener(toggle);      toggle.syncState();        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);      navigationView.setNavigationItemSelectedListener(this);        RequestPermission(this);  }    

Main.java (permission methods):

  private static final int MY_PERMISSIONS_REQUEST_READ_SMS = 226;    protected void RequestPermission(Activity activity)  {      if(ContextCompat.checkSelfPermission(activity, Manifest.permission.READ_SMS) != PackageManager.PERMISSION_GRANTED)      {          if(ActivityCompat.shouldShowRequestPermissionRationale(activity, Manifest.permission.READ_SMS)) {              return;          }          else          {              ActivityCompat.requestPermissions(activity, new String[] { Manifest.permission.READ_SMS              }, MY_PERMISSIONS_REQUEST_READ_SMS);          }      }  }    @Override  public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults)  {      switch(requestCode)      {          case MY_PERMISSIONS_REQUEST_READ_SMS:          {              if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)              {                  MessageAdapter messageAdapter = new MessageAdapter(GetMessages());                  RecyclerView recList = (RecyclerView) findViewById(R.id.messagesList);                  recList.setAdapter(messageAdapter);                    // CardView List                  LinearLayoutManager llm = new LinearLayoutManager(this.getApplicationContext());                  llm.setOrientation(LinearLayoutManager.VERTICAL);                  recList.setLayoutManager(llm);              }              else              {                  return;              }                return;          }      }  }