Forward declarations means the declaration of a method or variable prior to its implementation. Such declaration is necessary in C/C++ programming language in order to be able to use a variable or object before its implementation. In case, if we want to use a library code, then we need to create its header file and use it. But this is not a case in Java.
Java allows using a variable, class prior to its declaration and implementation.
Java allows using libraries code without any need of header files.
Following example showcases the same. Here we have used a class object before its declaration.
public class Tester{ public static void main(String args[]) { Test t = new Test(); t.display(); } } class Test { public void display() { System.out.println("Test"); } }
Test