Question

private String[][] var[]

This code compiles. But shouldn’t they make the array on type or variable?

Answer 1

The code is the same as this:

private String[][][] var;

All these forms are equivalent:

private String[][][] var;
private String[][] var[];
private String[] var[][];
private String var[][][];

And they all mean the same: a three-dimensional array of strings. The String var[][][] syntax may seem a bit weird, but it’s like that for making C/C++ programmers feel right at home in Java (that’s how you normally declare an array type in C/C++).

In Java, the String[][][] var syntax is preferred, as it makes clear that the type of var is String[][][], in the other syntax and its different variations the type information is split before and after the variable – although it’s perfectly legal from the compiler’s view point, it’s harder to read.

Even weirder, all these method declarations are legal and equivalent:

String[][][] m()  {return null;}
String[][] m() [] {return null;}
String[] m() [][] {return null;}
String m() [][][] {return null;}