Question

Is there any difference between between these two array declaration syntax in java?

int[] variableName; 

and

int variableName[];

Which one is preferred?

Answer 1

Although both syntaxes are equivalent, the int[] variableName; syntax is preferred. The int variableName[]; syntax is allowed just for making comfortable all the C/C++ programmers transitioning to Java.

One could argue that int[] x clearly states that integer array is the type of x, whereas in int x[] the actual type is split in two parts, one before and the other after the x variable, reading like integer is the type of the variable x which is an array making the declaration less readable and potentially confusing to a newcomer.

The readability problem is exacerbated if the array has more dimensions, for example all of these declarations are equivalent and valid:

int x[][][];
int[] x[][];
int[][] x[];
int[][][] x;  // this one is the easiest to read!

Also notice that the same considerations apply to all these valid, equivalent method declarations (the return type is the same in all cases) – but once again the last one is simpler to read:

int m() [][][] {return null;}
int[] m() [][] {return null;}
int[][] m() [] {return null;}
int[][][]  m() {return null;}  // this one is the easiest to read!