string manipulation java

1String newString = "Hello World";

1String manipulations:
2charAt(indexNumber): it returns the char at the given index
3length(): returns the total number of characters as int
4		length is ALWAYS one unit above the maximum index number
5		maxIndex: length()-1;
6concat(Value): Concatenation, concats the given value to the 
7String and returns a new value
8toLowerCase(): converts to lowercase and returns a new String
9toUpperCase(): converts to uppercase and returns a new String
10trim(): removes the unused spaces , and returns new String
11substring(beginning index, ending index): 
12creates substring of the string value from the beginning index 
13till the ending                   
14substring(beginning index): 
15creates substring of the string value from the beginning index 
16till the end of the stringreplace(old Value, new Value): new value 
17will be replaced with ALL the given old value, and returns new string 
18replaceFirs(old Value, new Value): 
19new value will be replaced with  the very first given old value, 
20  and returns new string
21indexOf(Value): 
22returns the index number of the first occurred character as an int             
23indexOf(Value): returns the index number of first 
24occurred character,as int
25lastIndexOf(Value): return the index number of 
26last occurred character, as int
27isEmpty(): identifies if the string is empty
28                true ==> string is empty,
29                false ==> String is not empty
30equals(str): checks if two string' visible texts are equal or not
31                    cares about the case sensitivity
32                        A == a  ==> false
33 equalsIgnoreCase(str):  checks if two string' visible texts 
34are equal or not
35                 does not care case sensitivity
36                    A == a ==> true
37 contains(str): checks if the str is contained in the string. 
38 returns boolean
39                    if str is conatined ==> true
40                    otherwise ==> false
41 startsWith(str): checks if the string starts with the given str. 
42 returns boolean
43                if starts with str ==> true
44                otherwise ==> false
45endsWith(str): checks if the string ended with the given str. 
46returns boolean
47                 if ended with str ==> true
48                    otherwise ==> false

1     String str = "abc";
2