Java program to concatenate the given strings using concat() method
Codeaft.java
class Codeaft
{
    public static void main(String args[])
    {
        String s="HELLO";
        s=s.concat(" WORLD");
        System.out.println(s);
    }
}
Output
codeaft@codeaft:~$ javac Codeaft.java
codeaft@codeaft:~$ java Codeaft
HELLO WORLD
codeaft@codeaft:~$
Java program to concatenate the given strings by passing object as a value
Codeaft.java
class Codeaft
{
    public static void main(String args[])
    {
        String s1="HELLO";
        String s2="WORLD";
        System.out.println(s1+s2);
    }
}
Output
codeaft@codeaft:~$ javac Codeaft.java
codeaft@codeaft:~$ java Codeaft
HELLO WORLD
codeaft@codeaft:~$
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