String concat Vs String + operator

String concat method used to Concatenates the given string

String h="Hello ";
h=h.concat("World");
System.out.println(h);
o/p Hello World

Using concat method we can Concatenates only strings.

String '+' operator used for Concatenates with another objects or primitive types.

String test="They are total "+7+"Fruits";
In the above string we concat string with integer primitive type.

String sample="The total percentage is "+ 70.5;
In the above string we concat string with float primitive type.