android substring

String substr=mysourcestring.substring(startIndex);

String substr=mysourcestring.substring(startIndex,endIndex);

String substr=mysourcestring.substring(mysourcestring.indexOf("characterValue"));

String substr=mysourcestring.substring(mysourcestring.indexOf("characterValue") + 1);

String hallostring = "hallo";
String asubstring = hallostring.substring(0, 1);