Chapter 1: Java Building Blocks

1. A, B, E. Option A is valid because you can use the dollar sign in identifiers. Option B is valid because you can use an underscore in identifiers. Option C is not a valid identifier because true is a Java reserved word. Option D is not valid because the dot (.) is not allowed in identifiers. Option E is valid because Java is case sensitive, so Public is not a reserved word and therefore a valid identifier. Option F is not valid because the first character is not a letter, $, or _.
2. D. Boolean fields initialize to false and references initialize to null, so empty is false and brand is null. Brand = null is output.
3. B, D, E. Option A (line 4) compiles because short is an integral type. Option B (line 5) generates a compiler error because int is an integral type, but 5.6 is a floating-point type. Option C (line 6) compiles because it is assigned a String. Options D and E (lines 7 and 8) do not compile because short and int are primitives. Primitives do not...