Regular local variables in source code are defined within a block , which may be the entire method body or some nested block 源代碼中一般的本地變量都定義在一個塊中,這個塊可能是一個完整的方法體或者是一個嵌套塊。
A local variable , already declared in an enclosing block and therefore visible in a nested block , cannot be redeclared in the nested block 一個語句塊里的變量,可以被其他語句塊再次聲明,但是不可以在嵌套語句塊聲明,但是在嵌套塊里他是可視的。