Can someone explain me this if statement [on hold]

I can't seem to understand the following code, especially the if statement. Could anyone help me out. Thank You.

public void printTriangle(String input) {    

        String tmp = input.substring(1);
        StringBuilder builder = new StringBuilder(tmp);
        builder = builder.reverse().append(input);
        String line = builder.toString();
        for(int i = 0; i < input.length(); i++){
            for(int j = 0; j < line.length(); j++){

                if(i + 1 == input.length() || Math.abs(j - line.length()/2) == i){
                    System.out.print(line.charAt(j));
                }else{
                    System.out.print(" ");
                }
            }
            System.out.println();
        }
    }}