compareTo with primitives - Integer int

Question

Is it better to write  int primitive1   3  primitive2   4  Integer a   new Integer primitive1   Integer b   new Integer primitive2   int compare   a compareTo b     or   int primitive1   3  primitive2   4  int compare    primitive1  gt  primitive2    1   0  if compare    0       compare    primitive1    primitive2    0   -1      I think the second one is better  should be faster and more memory optimized  But aren t they equal

User · Answer

Wrapping int primitive into Integer object will cost you some memory, but the difference will be only significant in very rare(memory demand) cases (array with 1000+ elements). I will not recommend using new Integer(int a) constructor this way. This will suffice :

Integer a = 3;

About comparision there is Math.signum(double d).

compare= (int) Math.signum(a-b);

User · Answer

Use Integer compare int  int   And don try to micro-optimize your code unless you can prove that you have a performance issue

User · Answer

If you are using java 8  you can create Comparator by this method   Comparator comparingInt i - gt  i     if you would like to compare with reversed order   Comparator comparingInt i - gt  -i

User · Answer

If you need just logical value  as it almost always is   the following one-liner will help you   boolean ifIntsEqual      Math max a b  - Math min a  b    gt  0     And it works even in Java 1 5   maybe even in 1 1  i don t have one   Please tell us  if you can test it in 1 5-   This one will do too   boolean ifIntsEqual      Math abs a-b    gt  0

User · Answer

They re already ints  Why not just use subtraction   compare   a - b    Note that Integer compareTo   doesn t necessarily return only -1  0 or 1 either

User · Answer

For performance  it usually best to make the code as simple and clear as possible and this will often perform well  as the JIT will optimise this code best    In your case  the simplest examples are also likely to be the fastest     I would do either  int cmp   a  gt  b    1   a  lt  b   -1   0    or a longer version  int cmp  if  a  gt  b     cmp    1  else if  a  lt  b     cmp   -1  else    cmp   0    or  int cmp   Integer compare a  b      in Java 7 int cmp   Double compare a  b      before Java 7   It s best not to create an object if you don t need to   Performance wise  the first is best   If you know for sure that you won t get an overflow you can use  int cmp   a - b     if you know there wont be an overflow    you won t get faster than this

User · Answer

May I propose a third    Integer  a  compareTo b

User · Answer

For pre 1 7 i would say an equivalent to Integer compare x  y  is   Integer valueOf x  compareTo y

[java] compareTo with primitives -> Integer / int

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