![public class OverloadingOrder { static void f(String s, inti) { print("String: " + s + ", int: " + i); } static void f(inti, String s) { print("int: " + i + ", String: " + s); } public static void main(String[] args) { f("String first", 11); f(99, "Int first"); } } Overloading in Action](https://image.slidesharecdn.com/14-initializationcleanup-100906020805-phpapp02/85/14-initialization-cleanup-8-320.jpg)
14 initialization & cleanup
- 2. Guarantees initialization of every objectEssentially a methodCalled when an object is created, even when no reference existsThe name of the constructor is the same as the name of the class Unusual type of method because it has no return value the new expression does return a reference to the newly created object public class Shape { public Shape() {}}Shape s = new Shape()Constructor
- 3. A constructor that takes no arguments is called the default constructor If you provide no constructor the default constructor is provided by default by the compiler.You can definitely have constructors with one or more argumentspublic class Rectangle{ private int length; private int breadth; public Rectangle(int length, int breadth) { length = length; breadth = breadth; }}Default Constructor
- 4. Method overloading allow the same method name to be used with different argument types. Constructors are methods and they can be overloaded too.Method overloading
- 5. public class Tree { int height; public Tree() { print("Planting a seedling"); height = 0; } public Tree(intinitialHeight) { height = initialHeight; print("Creating new Tree that is " + height + " feet tall"); } public void info() { print("Tree is " + height + " feet tall"); } public void info(String s) { print(s + ": Tree is " + height + " feet tall"); } }Overloading in Action
- 6. Test the Tree class by invoking each constructor and each methodExercise
- 7. Each overloaded method must take a unique list of argument types Even differences in the ordering of arguments are sufficient to distinguish two methods, although you don’t normally want to take this approach because it produces difficult-to-maintain code Distinguishing overloaded method
- 8. public class OverloadingOrder { static void f(String s, inti) { print("String: " + s + ", int: " + i); } static void f(inti, String s) { print("int: " + i + ", String: " + s); } public static void main(String[] args) { f("String first", 11); f(99, "Int first"); } } Overloading in Action
- 9. void f() {} int f() { return 1; }int x = f();f();You cannot use return value types to distinguishOverloading on return value
- 10. Reference of the current object that is available to no static methodsUsed widely in constructors to avoid ambiguityUse if you want to pass a reference of current object to another object.this
- 11. There is no destructor in JavaMemory is managed automatically by a garbage collector which is part of JVMA JVM may not even have a garbage collectorWhen garbage collector runs is not under programmers controlSystem.gc() – just a hintCommon garbage collection techniqueMark and Sweepfinalization()Called before an object is garbage collectedUseless method, should be avoided as you never know when it will be calledUse in JNI programs – malloc() , free()Destruction
- 12. Q&A