Ch2 Java Building Blocks

Question 1

An identifier is the name of a variable, method, class, interface, or package. There are 4 rules for legal identifiers. What are they?

Answer 1

• Identifiers must begin with a letter, a $ symbol, or a _ symbol.
• Identifiers can include numbers but not start with them.
• A single underscore _ is not allowed
• A java reserved word is not allowed (case sensitive)

Question 2

Does the following code compile?

public void test() {
var n = “hello”;
n = null;
var m = 1;
m = null;
}

Answer 2

It does not compile because the type for m is an int and a primitive int cannot be assigned null.
n = null compiles fine.