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javaintegerparseintvalue-of

Difference between parseInt() and valueOf() in Java?

How is parseInt() different from valueOf() ?

They appear to do exactly the same thing to me (also goes for parseFloat(), parseDouble(), parseLong() etc, how are they different from Long.valueOf(string) ?

Also, which one of these is preferable and used more often by convention?

Solution

  • Well, the API for Integer.valueOf(String) does indeed say that the String is interpreted exactly as if it were given to Integer.parseInt(String). However, valueOf(String) returns a new Integer() object whereas parseInt(String) returns a primitive int.

    If you want to enjoy the potential caching benefits of Integer.valueOf(int), you could also use this eyesore:

    Integer k = Integer.valueOf(Integer.parseInt("123"))

    Now, if what you want is the object and not the primitive, then using valueOf(String) may be more attractive than making a new object out of parseInt(String) because the former is consistently present across Integer, Long, Double, etc.