Introduction
A string is a sequence of characters. Strings are very important in Java. There are various methods of strings in Java. Some of them are as follows.
Creation of string
We can create a string in Java in the following way.
package demo99;
public class Demo99
{
public static void main(String args[])
{
String abc = "one way of creation";
String bcd = new String("another way of creation");
System.out.println(abc);
System.out.println(bcd);
}
}
Output
![creation of string]()
Copying Values of Array to String
We can copy the values contained by an array to the specific string in the following manner.
package demo99;
public class Demo99
{
public static void main(String args[])
{
char ch[] = {'c','o','m','p','u','t','e','r'};
String Str = String.copyValueOf(ch);
System.out.println(Str);
}
}
Output
![copying array values to string]()
Concatenation of Two Strings
There is a simple concat() method for the concatenation of strings in Java or we can also concat them in the following manner.
package demo99;
public class Demo99
{
public static void main(String args[])
{
String a = "COMPUTER ";
String b = "SCIENCE";
String c = a+b;
System.out.println("from first way "+c);
System.out.println("\n");
c = a.concat(b);
System.out.println("from second way "+c);
}
}
Output
![concatenation of strings]()
Comparing Two Strings
We can compare two strings using the equals() method as follows.
package demo99;
public class Demo99
{
public static void main(String args[])
{
String a = "COMPUTER";
String b = "COM";
String c = "COMPUTER";
if(a.equals(b))
{
System.out.println("strings are equal");
}
else
{
System.out.println("strings are not equal");
}
if(a.equals(c))
{
System.out.println("strings are equal");
}
else
{
System.out.println("strings are not equal");
}
}
}
Output
![comparing two strings]()
Getting Index of a Character or String From Other String
We can determine the index of a specific character or string from the other string using the indexOf() method in the following way.
package demo99;
public class Demo99
{
public static void main(String args[])
{
String a = "COMPUTER";
System.out.println("Index of character 'T' is "+a.indexOf('T'));
System.out.println("Index of string 'PUT' is "+a.indexOf("PUT"));
}
}
Output
![finding index]()
Replacing Characters in the String
We can easily replace a character in the string with another character using the replace() method as follows.
package demo99;
public class Demo99
{
public static void main(String args[])
{
String abc = "COMPUTER";
System.out.println("Replace 'R' with 'S' : "+abc.replace('R', 'S'));
}
}
Output
![replacing character from string]()
Changing the Case of Characters of the String
We can change the case of the characters of the string by using the toLowerCase() and toUpperCase() methods as follows.
package demo99;
public class Demo99
{
public static void main(String args[])
{
String abc = "COMPUTER";
System.out.println("To Lower Case: "+abc.toLowerCase());
System.out.println("To Upper Case: "+abc.toUpperCase());
}
}
Output
![changing case of characters in string]()
Summary
This article explains the various string functions in Java.