I am trying to emulate the behavior of a circular string, so I am appending the characters in the beginning of the string to the text, but I keep getting StringIndexOutOfBoundsException error, so I was hoping to see if this part of my code was wrong and why.

public MarkovModel(String text, int k) { order = k; StringBuilder stringBuffer = new StringBuilder(); for (int i = 0; i < order; i++) { stringBuffer.append(text.charAt(j)); }

text += stringBuffer.toString();

}