On Strings:

In the following list of string functions, 
        s, s1 and s2 denote objects of the class String,
	ch, ch1 and ch2 are values of type char, and
	m and n are integers >= 0.
	
s.length()           yields the number of characters in s.
s.charAt(n)          yields the character at position n in s.
                     where the index of the first position is 0.
s.substring(n)       yields the substring of s beginning in position n.
s.substring(n,m)     yields the substring of s beginning in position n
                     and ending at position m-1.
s1.compareTo(s2)     yields 0 if s1 and s2 are the same, <0 if s1 precedes
                     s2 alphabetically, and >0 if s2 precedes s2.
				     Case counts!
s1.equals(s2)        yields true iff s1 and s2 are literally equal.
s1.equalsIgnoreCase(s2)  does the right thing.
s1.startsWith(s2)    yields true iff s2 is a prefix of s1.
s1.startsWith(s2,n)  true iff s1, beginning in position n, contains s2.
s1.endsWith(s2)      true iff s2 is a suffix of s1.
s.indexOf(ch)        yields the position of the first occurrence of ch in s,
                     and -1 if ch is not in s.
s.indexOf(ch,n)      yields the position of the first occurrence at position
                     n or greater, of ch in s, and -1 if ch is not in s.
s.lastIndexOf(ch)    yields the position of the last occurrence of ch in s,
                     and -1 if ch is not in s.
s.lastIndexOf(ch,n)  yields the position of the last occurrence at position
                     n or earlier, of ch in s, and -1 if ch is not in s.
s.trim()             yields a copy of s without beginning and trailing blanks
                     and tabs.				     				  	
s.replace(ch1,ch2)	 yields a copy of s with all ch1's replaced by ch2's.
s.toUpperCase()      yields a copy of s with all lowercase letters replaced
                     by caps.
s.toLowerCase()      yields a copy of s with all uppercase letters replaced
                     by lowercase.
String.valueOf(x)    yields a text string for the value of x, in which x is
                     of a simple type or an object of a class for which the
					 method toString has been defined.