java String methods

These are common String methods. In all of these prototypes, i and j are int indexes into a string, s and t are Strings, and c is a char. cs is a CharacterSequence (eg, either String or StringBuilder).

Length
i =	s.length()	length of the string s.
Comparison (note: use these instead of == and !=)
i =	s.compareTo(t)	compares to s. returns <0 if ="=",">0 if s>t
i =	s.compareToIgnoreCase(t)	same as above, but upper and lower case are same
b =	s.equals(t)	true if the two strings have equal values
b =	s.equalsIgnoreCase(t)	same as above ignoring case
b =	s.startsWith(t)	true if s starts with t
b =	s.startsWith(t, i)	true if t occurs starting at index i
b =	s.endsWith(t)	true if s ends with t
Searching -- Note: All "indexOf" methods return -1 if the string/char is not found
i =	s.contains(cs)	True if cs can be found in s.
i =	s.indexOf(t)	index of the first occurrence of String t in s.
i =	s.indexOf(t, i)	index of String t at or after position i in s.
i =	s.indexOf(c)	index of the first occurrence of char c in s.
i =	s.indexOf(c, i)	index of char c at or after position i in s.
i =	s.lastIndexOf(c)	index of last occurrence of c in s.
i =	s.lastIndexOf(c, i)	index of last occurrence of c on or before i in s.
i =	s.lastIndexOf(t)	index of last occurrence of t in s.
i =	s.lastIndexOf(t, i)	index of last occurrence of t on or before i in s.
Getting parts
c =	s.charAt(i)	char at position i in s.
s1 =	s.substring(i)	substring from index i to the end of s.
s1 =	s.substring(i, j)	substring from index i to BEFORE index j of s.
Creating a new string from the original
s1 =	s.toLowerCase()	new String with all chars lowercase
s1 =	s.toUpperCase()	new String with all chars uppercase
s1 =	s.trim()	new String with whitespace deleted from front and back
s1 =	s.replace(c1, c2)	new String with all c1 characters replaced by character c2.
s1 =	s.replace(cs2, cs3)	new String with all cs2 substrings replaced by cs3.
Regular Expressions (as of Java 1.4) regexStr parameters are Strings, but see also java.util.regex.Pattern, ...
b =	s.matches(regexStr)	true if regexStr matches the entire string in s. Same as Pattern.matches(regexStr, s)
s1 =	s.replaceAll(regexStr, t)	replaces each substring that matches regexStr with String t
s1 =	s.replaceFirst(regexStr, t)	replaces first substring that matches regexStr with String t
sa =	s.split(regexStr)	array of all substrings terminated by regexStr or end
sa =	s.split(regexStr, count)	limited to applying regexStr only count times.
Static Methods for Converting to String
s =	String.valueOf(x)	Converts x to String, where x is any type value (primitive or object).
s =	String.format(f, x...)	[Java 5] Use format f to convert variable number of parameters, x to a string.
Comparator for sorting arrays and collections.
comp =	String.CASE_INSENSITIVE_ORDER	A static Comparator object that does case-insensitive comparisons for sorts and ordered Collections (eg, TreeMap, TreeSet, SortedMap, and SortedSet).