Java’s keyword final, just like JS’ keyword const, when used on a variable (be it a field, a parameter or a local variable), permanently seals the value stored in that variable, disallowing any further re-assignment to it. 
By value, it’s not just numerical 1s, but also references (a.K.a. pointers or memory addresses). 
In the statement above, the memory address of the array object created on the right side is permanently assigned to the variable layout00. 
We can’t re-assign layout00 to some other array any longer. Not even a null. 
However, the contents of that array, which variable layout00 points to, are still free to modify. 