question: public static NV [ ] concat ( final NV [ ] a , final NV [ ] b ) { if ( a == null && b == null ) return a ; if ( a == null ) return b ; if ( b == null ) return a ; final NV [ ] c = new NV [ a . length + b . length ] ; System . arraycopy ( a , 0 , c , 0 , a . length ) ; System . arraycopy ( b , 0 , c , a . length , b . length ) ; return c ; }
target:  Combines the two arrays, appending the contents of the 2nd array to the contents of the first array.