problem 1.8

gistfile1.java

public static void main( String[] args ) {
  String s11 = s1 + s1;
	if ( isSubstring( s11, s2 ) )
		System.out.println( "s2 is a rotation of s1.");
	else
		System.out.println( "s2 is not a rotation of s1." );
}

//check if s2 is a substring of s1
public static boolean isSubstring( String s1, String s2 ) {

}