Constructors are used to initialize instance variable state, as follows: : Constructor « Object Oriented « SCJP

1. SCJP
2. Object Oriented
3. Constructor

class Foo {
   int size;
   String name;
   Foo(String name, int size) {
      this.name = name;
      this.size = size;
   }
}

Foo class does not have a no-arg constructor. That means the following will fail to compile:

Foo f = new Foo();  // Won't compile, no matching constructor

but the following will compile:

Foo f = new Foo("Fred", 43);  // No problem. Arguments match the Foo constructor.