Blog

JDK 8 added a new method to String called join(). It concatenate two or more strings separated by a delimiter. In the below example first parameter to the method treated as delimiter.

public class StringJoin {
    public static void main(String[] args) {
        String result = String.join(", ", "I ", "am", "a", "Java" , "lover.");
        System.out.println(result);
        result = String.join(" ", "I ", "am", "a", "Java" , "lover.");
        System.out.println(result);
    }

output:

I , am, a, Java, lover.

I am a Java lover.

By Using concatenate operator (+) symbol , StringBuffer or StringBuilder also we can concatenate two or more Strings.

public class StringJoin {
    public static void main(String[] args) {
        String result = "I " + "am" + "a" + "Java" + "lover.";
        System.out.println(result);
        result = new StringBuffer("I ").append( "am")
                .append("a").append("Java").append("lover.").toString();
        System.out.println(result);
        result = new StringBuilder("I ").append( "am")
                .append("a").append("Java").append("lover.").toString();
        System.out.println(result);
    }
}

output:

I amaJavalover.
I amaJavalover.
I amaJavalover.