difference between abstract class and interface in java

Java interface and abstract class small notes@author IxenosInterface 1. The interface does not have a constructor because the interface is not instantiated2. Anonymous objects if the constructor that uses the interface also simply represents a covariant anonymous object that implements the interface3. The member variables in the interface are the public sta

;publicstaticfinal that belongs to graphic class doublepi=3.14;publiccircle (Stringname,doubler) {super (name); THIS.R =r;} The area of Publicvoidgetarea () {System.out.println (name+) is: "+pi*r*r);} The perimeter of Publicvoidgetlength () {System.out.println (name+) is: ' +2*pi*r ';}} Rectangle belongs to the one classrectextendsmyshape{intwidth;intheight;public in the graph Rect (StrIngname,intwidth,intheight) {super (name);this.width=width;this.

(P.kouhao ());Ten } One //System.out.println (A.kouhao ()); A //System.out.println (B.kouhao ()); - - } the - - } - + Abstract classperson{ - PrivateString name; + PublicPerson (String aname) { A This. name=Aname; at } - PublicString GetName () { - return This. Name; - } - Public AbstractString Kouhao (); - } in - classEmployee extends person{ to PrivateString Alaname; + PublicEmp

Abstract class animal{???? Public abstractvoid eat (); }class Dog extends animal{ ???? Public void eat () { ???????? System. out. println (" The dog eats bones . ");????}}class Cat extends animal{ ???? Public void eat () { ???????? System. out. println (" The cat eats the mouse ");????}}

In object-oriented concepts, all objects are depicted by classes, but conversely, not all classes are used to depict objects, and if a class does not contain enough information to depict a specific object, such a class is an abstract class.Abstract classes In addition to the object cannot be instantiated, other functions of the

barking, but how to make sure, this method teaches abstraction.When a class describes a thing, there is not enough information to describe the thing, and this class is abstract.Abstract class Canine {abstract void sing ();//four legs, two eyes, running, jumping ...} Class D

Not much to say, the first paragraph of code. Public classabstract{ Public Static voidMain (string[] args) {Cl2 c=NewCl2 (); C.method (); }}Abstract classabc{ Public Abstract voidmethod (); }classCl2extendsabc{ Public voidmethod () {System.out.println ("Concrete Method"); }}There can be no abstract method in an abstract