Best way of concatenate String in java -

Best way of concatenate String in java -

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string concatenation: concat() vs + operator 10 answers

what best way concatenate 2 strings in java. best performance , less memory usage. please help me..!

stringbuilder stringbuilder = new stringbuilder(firststring); stringbuilder.append(secondstring); string string = stringbuilder.tostring();

but according @a_horse_with_no_name next more efficient

stringbuilder sb = new stringbuilder(firststring.length() + secondstring.length()); sb.append(firststring); sb.append(secondstring); string string = sb.tostring();

java