Intent intent = new Intent(); intent.setClassName(<package name>, <class name>); startActivity(intent);

Intent i=new Intent;ComponentName com= new ComponentName(<Package Name> , <Calss Name>); i.setComponent(com); startActivity(i); 

Intent i = new Intent();ComponentName comp = new ComponentName("com.Android.camera","com.android.camera.GalleryPicker");i.setComponent(comp);i.setAction("android.intent.action.VIEW");startActivity(i);

Intent mIntent = new Intent();ComponentName comp = new ComponentName("com.android.camera","com.android.camera.Camera");mIntent.setComponent(comp);mIntent.setAction("android.intent.action.VIEW");startActivity(mIntent);

Intent intent = new Intent();ComponentName cn = new ComponentName("com.android.htmlviewer", "com.android.htmlviewer.HTMLViewerActivity");intent.setComponent(cn);Uri uri = Uri.fromFile(new File("/sdcard/demo.txt"));intent.setDataAndType(uri, "text/plain");startActivity(intent);