Java chapter 2

You can use this class to display dialog boxes a. JOptionPane b. BufferedReader c. InputStreamReader d. DialogBox

a. JOptionPane

true or false: a left brace in a java program is always followed by a right brace later in the program.

true

true or false: a variable must be declared before it can be used

true

true or false: you cannot change the value of a variable whose declaration uses the final key word

true

which of the following are not valid println statements? (indicate all that apply): a. System.out.println + "Hello World"; b. System.out.println("Have a nice day"); c. out.System.println(value); d. println.out(Programming is great fun);

a. System.out.println + "Hello world"; c. out.System.println(value); d. println.out(programming is great fun);

a group of statements, such as the contents of a class or a method, are enclosed in _________; a. braces {} b. parentheses () c. brackets [] d. any of these will do

a. braces {}

this type of operator lets you manually convert a value, even if it means that a narrowing conversion will take place. a. cast b. binary c. uploading d. dot

a. cast

which scanner class ethod would you use to read a double as input? a. nextDouble b. getDouble c. readDouble d. none of these; you can't

a. nextDouble

the negation operator is _______; a. unary b. binary c. ternary d. none of these

a. unary

these characters mark the beginning of a single-line comment a. // b. /* c. */ d. /**

a.//

These characters mark the beginning of a multi-line comment a. // b./* c.*/ d./**

b. /*

which of thee following are not valid assignment statements? (indicate all that apply); a. total = 9; b. 72 = amount; c. profit = 129 d. letter = 'w';

b. 72 = amount; c. profit = 129

The following data 72 'A' "Hello World" 2.8712 are all examples of __________; a. variables b. literals c. strings d. none of these

b. literals

Which Scanner class method would you use to read a string as an input? a. nextString b. nextLine c. readString d. getLine

b. nextLine

This key word is used to declare a named constant. a. constant b. namedConstant c. final d. concrete

c. final

Every complete statement ends with a _______: a. period b. parenthesis c. semicolon d. ending brace

c. semicolon

When Java converts a lower-ranked value to a higher-ranked type, it is called a(n) __________; a. 4-bit conversion b. escalating conversion c. widening conversion d. narrowing conversion

c. widening conversion

these characters mark the beginning of a documentation comment a. // b. /* c. */ d. /**

d. /**

true or false: comments that begin with // can be processed by javadoc.

false

true or false: if one of an operator's operands is a double, and the other operand is an int, java will automatically convert the value of the double to an int.

false

true or false: variable names may begin with a number.

false