Sams Teach Yourself Java 2 in 21 Days, Second Edition

Q&A

Q1:	I declared a variable inside a block statement for an if . When the if was done, the definition of that variable vanished. Where did it go?
A1:	In technical terms, block statements form a new lexical scope . What this means is that if you declare a variable inside a block, it's visible and usable only inside that block. When the block finishes executing, all the variables you declared go away. It's a good idea to declare most of your variables in the outermost block in which they'll be needed—usually at the top of a block statement. The exception might be very simple variables, such as index counters in for loops, where declaring them in the first line of the for loop is an easy shortcut.
Q2:	Why can't you use switch with strings? ...