Android Studio failed to convert drawable into a drawable

 public void createDatabase(Context myContext) throws IOException {
    String sPackName = myContext.getPackageName();
    InputStream assetsDB = myContext.getAssets().open("myDatabase");
    OutputStream dbOut = new FileOutputStream("/data/data/"+sPackName+"/database");
 
    byte[] buffer = new byte[1024];
    int length;
    while ((length = assetsDB.read(buffer))>0){
      dbOut.write(buffer, 0, length);
    }
 
    dbOut.flush();
    dbOut.close();
    assetsDB.close();
}

if(Build.MANUFACTURER.equals("unknown")) {
		// Emulator
	}

		// Error
                String s = null;
		Log.e("bla", s); // !!! error Log.e println needs a message error.
                // OK
		String s = null;
		Log.e("bla", s+""); // OK 

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class MainClass {
	public static void main(String[] arg) {
		String[] arrayOfString = {"nothing", "Hello", "people"
				, "bye-bye", "hello", "world!", "End" };
		   List<String> arrayList = new LinkedList<String>();
            for(String s: arrayOfString)
		     arrayList.add(s);

		    Collections.shuffle(arrayList);

		    System.out.println(arrayList);
		    
		  }
}
/*
[hello, world!, bye-bye, nothing, people, End, Hello]
*/