Strings Introduction

String are most widely used in any programming language. String is basically sequence of characters and. in Java Strings are treated as objects.

There are 2 ways you can declare String in Java:

1.          String Literal:

Syntax: String name= “String you wanted”;

Sample Code: String str= “Nihal Kurre”;

2.          Using new KeyWord:

Syntax: String name=new String( “String you wanted”);

Sample Code: String str= new String( “Nihal Kurre”);

Note: Strings are immutable [It means once if they are declared they cannot be changed]

What can you do with Strings??

You can almost do anything design algorithms, manipulate, convert into objects etc.

Java String class provides a lot of methods to perform and manipulate such as :

Equals(), slpit(), length(), compareTO(), substring(), concate(), indexed(), repace(), charAt().. etc.

No:	Method		Description
1	length()		Returns length of a given string
2	charAt(int index)		Returns char value of index
3	Boolean contains()		Returns true/false
4	String substring(int begin index)		Returns substring for given index
5	String substring(1stIndex, Last index)		Returns substring for given begin index to end index
6	String substring(1stIndex)		Return the substring value
7	Boolean isEmpty()		Returns true/false
8	Equals(Object another)		Compares 2 objects
9	String replace(charSeq old, CharseqNew)	Replace your old char char with given new char
10	Int indexOf(int char)		Returns index of char value
11	int indexOf(int ch, int fromIndex)		returns specified char value index starting with given index
12	String toUpperCase()		Convers string to upper case
13	String toLowerCase()		Convers string to lower case
14	String trim()		Removes beginning and ending spaces in the given string
15	String valueOf(int value)		Convert given type into string and it is overloaded

Did you Know??

o        How to create an immutable class?

o        What is string constant pool?

o        What code is written by the compiler if you concat any string by + (string concatenation operator)?

o        What is the difference between StringBuffer and StringBuilder class?