Java Comparator class to sort arrays

Question

Say  we have the following 2-dimensional array   int camels       new int n  2     How should Java Comparator class be declared to sort the arrays by their first elements in decreasing order using Arrays sort camels  comparator   The compare function for reference is    Override public int compare int   a  int    b        return b 0  - a 0

User · Answer

Just tried this solution  we don t have to even write int   int     twoDim       1  2      3  7      8  9      4  2      5  3      Arrays sort twoDim   a1 a2  - gt  a2 0  - a1 0      This thing will also work  it automatically detects the type of string

User · Answer

The answer from  aioobe is excellent  I just want to add another way for Java 8    int     twoDim       1  2      3  7      8  9      4  2      5  3       Arrays sort twoDim   int   o1  int   o2  - gt  o2 0  - o1 0     System out println Arrays deepToString twoDim      For me it s intuitive and easy to remember with Java 8 syntax

User · Answer

How should Java Comparator class be declared to sort the arrays by their first elements in decreasing order         Here s a complete example using Java 8   import java util     public class Test        public static void main String args               int     twoDim      1  2    3  7    8  9    4  2    5  3              Arrays sort twoDim  Comparator comparingInt a - gt  a 0                                          reversed              System out println Arrays deepToString twoDim              Output     8  9    5  3    4  2    3  7    1  2       For Java 7 you can do   Arrays sort twoDim  new Comparator lt int   gt           Override     public int compare int   o1  int   o2            return Integer compare o2 0   o1 0                  If you unfortunate enough to work on Java 6 or older  you d do   Arrays sort twoDim  new Comparator lt int   gt           Override     public int compare int   o1  int   o2            return   Integer  o2 0   compareTo o1 0

[java] Java Comparator class to sort arrays

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