6.2.2 The String class

The String class provides methods for manipulating strings some of these methods are detailed below. For a full list look at the Java API documentation.

charAt	Returns the charcater at the specified position in the string. The positions in the string are 0 based.
endsWith	Returns true if the string the method is called on ends with the string specified.
indexOf	Returns the position of the specified string with in the string the method is called on.
length	Returns the length of the string.
substring	Returns a substring of the string the method is called on.
toLowerCase	Returns the string lower-cased.
toUpperCase	Returns the string upper-cased.
valueOf	This static method converts the supplied datatype to a string.

Source

Java API documentation.