part of the a-String : efg
String "efg" was found in "defghijk", starts at position 1
String "efg" not found in "eghijklm"

public class StringCompare {
   public static void compare(String tmp, String b) {
      // search this tmp-String in the b-String
      // use the methode indexOf
      // this methode will return -1 if the tmp-String is not
      // in the b-String 
 
      int pos;
      if ((pos = b.indexOf(tmp)) != -1) {
         System.out.println("String \"" + tmp + "\" was found in \"" + 
         b +"\", starts at position " + pos);
      }
      else { 
         System.out.println("String \"" + tmp + "\" not found in \"" +
         b + "\""); 
      }
   }
 
   public static void main(String args[]) {
      String a = "abcdefgh";
      String b = "defghijk";
      String c = "eghijklm";
 
      // take the part of the a-String you want to find in
      // the b-String, here "efg"
      System.out.println("part of the a-String : " + a.substring(4,7));
      compare(a.substring(4,7), b);
      compare(a.substring(4,7), c);
   }
}