If an Application is a non-system application it must have a launch Intent by which it can be launched. If the launch intent is null then its a system App.
Example of System Apps: "com.android.browser.provider", "com.google.android.voicesearch".
For the above apps you will get NULL when you query for launch Intent.
PackageManager pm = getPackageManager();
List<ApplicationInfo> packages = pm.getInstalledApplications(PackageManager.GET_META_DATA);
for(ApplicationInfo packageInfo:packages){
if( pm.getLaunchIntentForPackage(packageInfo.packageName) != null ){
String currAppName = pm.getApplicationLabel(packageInfo).toString();
//This app is a non-system app
}
else{
//System App
}
}