Double.valueOf (s) vs Double.parseDouble

Question

Moving the object to double and noticed both of these methods. I see that parseDouble is from 1.2. Why add this method if it essentially performs the same functions as valueOf (s)?

Answer 1

parseDouble() returns the primitive double value. valueOf() returns an instance of the double wrapper class. Before Java 5 introduced autoboxing, that was a very significant difference (and many claim it still exists).

Answer 2

Because it is not the same thing. valueOf() creates a Double object, which is often not needed. parseDouble() no. With autoboxing, it has valueOf(String) , which is no longer needed, but therefore has backward compatibility.

Answer 3

If you just need to use a value (primitive), use parseDouble(String s) , the cost is less. valueOf(String s) returns a double class that wraps a primitive double value.