Also, you can't construct a java String without copying the data into it, because String is immutable. In other languages like c++ or rust the string type is mutable so you don't need an extra copy. Java doesn't even special case blessed APIs like StringBuilder to avoid the extra copy, since StringBuilder itself doesn't have a method to consume the inner buffer, you can only create a string from it without touching the buffer even though it's not the normal usage to create multiple strings from a given StringBuilder.

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throeaway9 4 days ago | parent [-]

For cases where a string repeats itself, you can use String.intern() to reuse data.

	▲	layer8 4 days ago \| parent [-]
		String.intern() doesn't reuse the data per se. It merely gives you a canonical instance with the same value as the String instance you invoke it on (unless it's the first time it is invoked for that value, in which case it returns the same instance you already have in hand). At that point the latter duplicate instance has already been constructed. The only benefit in terms of memory is that the duplicate instance might be garbage-collected earlier if the program stops referencing it and uses the interned instance instead. Also, String.intern() can be quite slow compared to something like ConcurrentHashMap.putIfAbsent().