JAVA各章知识点和难点.pptVIP

第2章：类与对象的基本概念 1、类与对象 类的成员 变量成员（类变量和实例变量） 方法成员（类方法和实例方法） 2、类成员的访问控制 默认 public protected private 能将程序补充完整的是（ ） class Person{ private int a; public int change(int m){ return m; } } public class Teacher extends Person{ public int b; public static void main(String arg[ ]){ Person p = new Person( ); Teacher t = new Teacher( ); int i; _______D_____________； } } A. i=m; B. i=b; C. i=p.a; D. i=p.change(50); 能将程序补充完整的是：（ ） class Person{ String name, department; int age; public Person ( String n ){ name = n; } public Person ( String n , int a ){ name = n; age = a ; } public Person ( String n, String d , int a){ ____C__________ ; department = d ; } } } Person (n , a) B. this( Person (n , a) ) C. this( n, a) D. this( name, age ) 第3章：类的方法 异常处理 try--catch--finally throw throws 自定义异常 public class A { public static void main(String arg[]){ try{ System.out.println(try); } catch(Exception e){ System.out.println(catch); } finally{ System.out.println(finally); } } } import java.io.*; public class T { public static void main( String [ ] arg) { System.out.print( start ) ; try { System.out.print(hello the world ) ; throw new FileNotFoundException(); } catch ( FileNotFoundException e ) { System.out.print( file not foubd) ; } catch ( EOFException e ) { System.out.print( end of file exception ) ; } } } public class T { public static void throwit ( ) { System.out.print( “throwit ” ) ; throw new RuntimeException(); } public static void main( Str