About Question com.enthuware.ets.scjp.v6.2.404 :

[devlam]

int[ ] a[ ] = new int [5][4] ;
int[ ] a[ ] = new int[4][ ] ;

In the explanations of the above array declaration/initialization there is nothing said about the second dimension. This may look like there is no difference, but the first one is actually creating references to arrays of length 4 in the first dimension. The second doesn't put these references.

[admin]

Explanation has now been enhanced.
thank you for your feedback!