Five Lines: Which Compile, and What Each One Creates

A class with one constructor taking a name, and one static counter. For each line below, decide whether it compiles and how many objects exist afterwards. Write all five down first.

java

class Item {
    static int made = 0;
    String name;
    Item(String name) { this.name = name; made++; }
}

java

Item a = new Item("pen");
Item b = new Item();
Item c = a;
System.out.println(Item.made);
System.out.println(a.made);

Which of the five compile, and what is true afterwards?

Each line, whether it compiles, and what it does
Line	Compiles?	What happens
`new Item("pen")`	Yes	One object exists; `made` is 1
`new Item()`	No	Writing a constructor removed the free no-argument one
`Item c = a;`	Yes	No new object — a second name for the first one
`Item.made`	Yes	Reads the one counter through the class name, which is the clear spelling
`a.made`	Yes	Reads the same one counter through a reference, which compiles and misleads

The last one is worth arguing about. It is legal and it reads as though made belongs to a. Most style guides and most compilers' warnings ask for the class name, because there is only ever one of it.