Multi classes1. Phn bit Object and class.publicclassDemoJavaBasic {publicstaticvoidmain(String[] args) { Aa1 =newA(); a1.setName(Phuong); System.out.println(a1.getName()); Aa2 =newA(); a2.setName(Anh Viet); System.out.println(a2.getName()); Bb1 =newB(); }}classA {privateStringname;publicString getName() {returnname; }publicvoidsetName(String name) {this.name=name; }}classB {} Khi nim tra tng trong mt lp thc th To cc i tng khc nhau t class Cc i tng c chung cc thuc tnh v chung phng thc . i tng ging nhau phng thc thi hnh nhng khc nhau cc thuc tnh. New A(); Thc cht y l qu trnh gi ti hm kho to mc nh construc m tha k. This.name Tr ti chnh gi tr ca lp c gn bi cc thuc tnh cc b truyn vo Kt lun Mt lp th c cc phng thc ging nhau, thuc tnh khc nhau khai bo bi cc i tng To ra i tng bng cu lnh NEW Hm khi to mc nh ca i tng m chng tha k. i tng c thay i cc gi tr l cc thuc tnh bn trong class thng qua Set. i tng c chung phng thc trong mt class. Gii thch Phn bit class v i tng:+ Classc chungthuc tnh v phng thc cho Object khiimplement.V d:classPerson. Con ngi th phi ctn (thuc tnh), mun c tn th ta phi t tn (phng thc).i tng l mt i tng c thno . V d: classPerson th ta s c personvi tn c th no nh l:Phnghay lVit. on code trn ta cclass A,class Bvto ra cc i tnga1, a2, b1. Khi to mt i tng chng hnga1th i tng sc to bi mt hm khi to y hm khi to l mc nh tha k t classjava.lang.Object.Lu : T khathis( chnh n) trong phng thcsetNamecaclass A. Cinamem n tr ti tc l thuc tnhnamecaclass A.