why constructor doesn't have any return type?

[kaka]

Can any one give answer asap....

[Zack]

Because the constructor simply returns the new object automatically.

Integer a = new Integer(1);

The constructor could look something like this:

public Integer(int x) {
    this.value = x;
}

It doesn't need to return anything because it is understood that the new Integer(1) is a reference to the new object being created.