java - Organizing array of unknown number of constants in all possible ways -

this question has answer here:

• permutations/combinatorics library java? [closed] 2 answers
• permutation of array 8 answers

what best way of looping through array, ending organizing in possible ways can organized in?

suppose have array:

{a, b, c, d} 

what organize so:

{b, a, c, d} {b, d, c, a} 

and forth, looping around creating 1 array analyze per looping.

thank you,