Java Strings

String is a sequence of characters. It allows us to store multiple characters without using character array. String is immutable means it cannot be modified when assigned

Java string can be implemented using two classes as

1. String class
2. String Buffer

String class

String class is already defined in java's java.lang Package which is used to create strings

Creating a String

The String class object can be created implicitly of explicitly. To create a string implicitly, a String literal is used to create String object automatically. Java Strings are more reliable and predictable.

Syntax

String string_name = "your String";

or

String string_name = new String("Your String");

In first Syntax You can directly assign the string while creating an object. In second Syntax you can pass the string to it's constructor while creating an object. Both are valid.

Program Example

Below example shows how to create and print the String in java.

class StringDemo
{
    String first = "AndroidBerry";
    String second = new String(" Easy Learning");
    String third = first + second; // it concatenates two strings
    StringDemo()
    {
	System.out.println(first);
	System.out.println(second);
	System.out.println(third);
    }
    public static void main(String args[])
    {
	StringDemo sd = new StringDemo();
    }
}

Output

In above example,We have created three strings first,second and third. first string directly assigns the string and second string is assigned in the costructor of String class. third string concatenates first and second string into single string.

String Arrays

String array allows us to store more than one strings into a single String object. Without array we need to create seperate string objects of storing single values.It saves our time and memory space.

Syntax of creating String array

String string_name [] = new String [size] = {"string1","string2","stringN"};
    
or
    
String string_name [] = {"string1","string2","stringN"};

String array Example

class StringArray
{
    String cities [] = {"USA","Canada","India","Russia","Japan"};
    StringArray()
    {
       int i;
       for (i=0;i < cities.length();i++)
          System.out.println("i = "+cities[i]);
    }
    public static void main(String args[])
    {
       StringArray s1 = new StringArray();
    }
}

String class methods

There are large number of String methods are available for String manipulation. They saves our time in the program from defining our own methods.

Syntax of using String methods

String string_name = "your String";
string_name.methodName();

Assume we have two strings as

String s1 = "Android";
String s2 = " Berry" // with empty character space start
int num = 123;