String in Java

#java #beginners #basic

The String in Java is a sequence of characters used to store and manipulate text.It is one of the most used classes in Java.

Each character in a string is stored using 16-bit Unicode (UTF-16) encoding.
Strings are immutable, meaning their value cannot be changed after creation.

Example

String str = "Hello";

str.concat(" World");

System.out.println(str);

Output
Hello

Because concat() creates a new string instead of modifying the old one.

Ways to Create String

1. String Literal

Example:1

public class Demo {
    public static void main(String[] args) {

        String name = "Harini";

        System.out.println(name);
    }
}

Output
Harini

Why is this called String Literal?

String name = "Harini";

"Harini" → String literal
It is directly written inside double quotes.
Java stores it inside the String Constant Pool.

Example: 2

public class Test {
    public static void main(String[] args) {

        String a = "Java";
        String b = "Java";

        System.out.println(a == b);
    }
}

Output:
true

Because both a and b point to the same object in the String pool.

String Pool

Java stores string literals in a special memory area called the String Constant Pool.

2. Using new Keyword

Example

public class Demo {
    public static void main(String[] args) {

        String s1 = new String("Java");
        String s2 = new String("Java");

        System.out.println(s1);
        System.out.println(s2);

        System.out.println(s1 == s2);
        System.out.println(s1.equals(s2));
    }
}