Why is this Java program showing no error?

Question

Consider the below code,

I forgot to define the method name, just the code within the block.

public class Demo {

    {
    Apple ap;
    // Display price of Winesap.
    System.out.println("Winesap costs " + Apple.Winesap.getPrice()
            + " cents.\n");
    // Display all apples and prices.
    System.out.println("All apple prices:");
    for (Apple a : Apple.values())
        System.out.println(a + " costs " + a.getPrice() + " cents.");
    }

}

is it because blocks{} in java defines a scope?

A block {} defines the scope in Java. Each time you start a new block, you are creating a new scope. A scope determines what objects are visible to other parts of the program. It also determines the lifetime of these objects. Many other computer languages define 2 general category of scopes : global and local.

It is an [instance initialization block](http://stackoverflow.com/questions/3987428/what-is-an-initialization-block) ([more at Oracle](http://docs.oracle.com/javase/tutorial/java/javaOO/initial.html)). — icza, Oct 07 '14 at 07:13
@Suresh Atta: I am just guessing what use this block will have... — Farhan stands with Palestine, Oct 07 '14 at 07:14
we need more of you ;), why would i ask? just answer directly — CodeFanatic, Oct 07 '14 at 07:14
@sᴜʀᴇsʜᴀᴛᴛᴀ hhahahaha you're exactly right. How weird is that? :P — Leo, Oct 07 '14 at 07:14
Even Java defines actually 3 categories of blocks. *static blocks*, *instance level blocks* and *method local blocks*. — TheLostMind, Oct 07 '14 at 07:14

score 4 · Accepted Answer · answered Oct 07 '14 at 07:14

4

What you've got there is an instance initializer, as described by section 8.6 of the JLS.

It's executed before the body of any constructor when an instance is created - just like field initializers.

answered Oct 07 '14 at 07:14

Jon Skeet

1,421,763
867
9,128
9,194

Why is this Java program showing no error?

1 Answers1