Clarification on String concatenation in java -


this question has answer here:

i beginner in java, please go easy on comments.

    string test = "test";     test.concat("test");     system.out.println("concatenated string: " +test);     system.out.println("concatenated test: " +test.concat(test));

why first print statement not print testtest, while second 1 does? might basic question, not find answer online. can please explain?

because you're not assigning concatenated string value (as concat() returns resulting string), lost.

if want result, need do:

test = test.concat("test");

the second println() works, because resulting concatenated string returned, captured , used system.out.println(), lost outside of println() not assigned (so if check test after, still contains "test").

here's doc: http://docs.oracle.com/javase/7/docs/api/java/lang/string.html#concat%28java.lang.string%29


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