/* # Constructor JLS7 8.8 Cannot be `abstract`, `static`, `final`, `native`, `strictfp`, or `synchronized`. Can however be `private` to prevent object construction, e.g. in static utility classes. */ public class ConstructorCheat { public static void main(String[] args) { /* # Default constructor Constructor automatically defined if you don't define any other constructor. Sets all fields to their default values. */ { class Class { Class(int i) {} } // ERROR: we did define a constructor Class(int), // so the default constructor was not defined. //new Class(); // TODO: is an empty constructor equivalent to the default constructor? } /* # Method with the same name as the constructor Horrendous, but valid. A constructor is only considered if there is no return value. */ { class Class { int i; Class(int i) { this.i = i; } int Class() { return this.i; } } assert new Class(1).Class() == 1; } /* # Constructor inheritance Does not exist. You have to duplicate code: http://stackoverflow.com/questions/1644317/java-constructor-inheritance Likely rationale: otherwise all classes would have an empty constructor derived from `Object`, and it does not make much sense to many classes. */ { class Base { public int i; Base(int i) { this.i = i; } } // ERROR: would generate only the default constructor, // which calls super(), which does not exist. //class Class extends Base {} // OK. class Class extends Base { Class(int i) { super(i); } } assert new Class(1).i == 1; } } }