Fastest way for read an entire text file in one line Java

Question

I've got a class in which constructor should collaborate.

public class Text(){
    private String text;

    public Text(String text){
        this.text = text;
    }

    public Text(InputStream input){
        this(AND NOW?);
    }
}

I tried using Scanner... but 1.I cant close it 2.It is too slow.

How i can read all text in one line in the fastest way?