Java：从控制台读取直到出现空行

我写了这个方法，永无休止。它没有打印我传递的内容，为什么？

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;

class Main {

   public void readFromConsole() {

          ArrayList<String> wholeInput= new ArrayList <String>();  

          InputStreamReader isr = new InputStreamReader(System.in);
          BufferedReader br = new BufferedReader(isr);

           try {
                String line = null;
                while (!(line = br.readLine()).equals(" ")){
                wholeInput.add(line);
           }

        }
        catch(IOException e){
            e.printStackTrace();
        }

       for (int i =0; i<wholeInput.size();i++){
              System.out.println(wholeInput.get(i));
       }
    }

}

" "不是空行，而是空格。尝试""

while (!(line = br.readLine()).trim().equals("")){