How to trim strings in java without creating a new object?

Question

I have a large text file(about 20 million lines) which has lines in the following format :

<string1>, <string2>

Now those strings may have trailing or leading whitespaces which I want to remove on reading the file.

I am currently using trim() for this purpose but since String in Java is immutable, trim() is creating a new object per trim operation. This is leading to too much wastage of memory.

How can I do it better?

Answer 1

I would be surprised if the immutable String class is causing problems; the JVM is very efficient and the result of many years of engineering work.

That said, Java does provide a mutable class for manipulating strings called StringBuilder. You can read the docs here.

If you are working across threads, consider using StringBuffer.