public class Dog{ 
  String breed; 
  int age; 
  String color; 
  void barking(){ 
  } 
   
  void hungry(){ 
  } 
   
  void sleeping(){ 
  } 
} 

public class Puppy{ 
  public Puppy(){ 
  } 
 
  public Puppy(String name){ 
   // 这个构造器仅有一个参数：name 
  } 
} 

public class Puppy{ 
  public Puppy(String name){ 
   //这个构造器仅有一个参数：name 
   System.out.println("Passed Name is :" + name ); 
  } 
  public static void main(String []args){ 
   // 下面的语句将创建一个Puppy对象 
   Puppy myPuppy = new Puppy( "tommy" ); 
  } 
} 

/* 实例化对象 */
ObjectReference = new Constructor(); 
/* 访问其中的变量 */
ObjectReference.variableName; 
/* 访问类中的方法 */
ObjectReference.MethodName(); 

public class Puppy{ 
  int puppyAge; 
  public Puppy(String name){ 
   // 这个构造器仅有一个参数：name 
   System.out.println("Passed Name is :" + name ); 
  } 
 
  public void setAge( int age ){ 
    puppyAge = age; 
  } 
 
  public int getAge( ){ 
    System.out.println("Puppy's age is :" + puppyAge ); 
    return puppyAge; 
  } 
 
  public static void main(String []args){ 
   /* 创建对象 */
   Puppy myPuppy = new Puppy( "tommy" ); 
   /* 通过方法来设定age */
   myPuppy.setAge( 2 ); 
   /* 调用另一个方法获取age */
   myPuppy.getAge( ); 
   /*你也可以像下面这样访问成员变量 */
   System.out.println("Variable Value :" + myPuppy.puppyAge ); 
  } 
} 

import java.io.*; 
public class Employee{ 
  String name; 
  int age; 
  String designation; 
  double salary; 
  // Employee 类的构造器 
  public Employee(String name){ 
   this.name = name; 
  } 
  // 设置age的值 
  public void empAge(int empAge){ 
   age = empAge; 
  } 
  /* 设置designation的值*/
  public void empDesignation(String empDesig){ 
   designation = empDesig; 
  } 
  /* 设置salary的值*/
  public void empSalary(double empSalary){ 
   salary = empSalary; 
  } 
  /* 打印信息 */
  public void printEmployee(){ 
   System.out.println("Name:"+ name ); 
   System.out.println("Age:" + age ); 
   System.out.println("Designation:" + designation ); 
   System.out.println("Salary:" + salary); 
  } 
}

import java.io.*; 
public class EmployeeTest{ 
 
  public static void main(String args[]){ 
   /* 使用构造器创建两个对象 */
   Employee empOne = new Employee("James Smith"); 
   Employee empTwo = new Employee("Mary Anne"); 
 
   // 调用这两个对象的成员方法 
   empOne.empAge(26); 
   empOne.empDesignation("Senior Software Engineer"); 
   empOne.empSalary(1000); 
   empOne.printEmployee(); 
 
   empTwo.empAge(21); 
   empTwo.empDesignation("Software Engineer"); 
   empTwo.empSalary(500); 
   empTwo.printEmployee(); 
  } 
} 

C :> javac Employee.java 
C :> vi EmployeeTest.java 
C :> javac EmployeeTest.java 
C :> java EmployeeTest 
Name:James Smith 
Age:26
Designation:Senior Software Engineer 
Salary:1000.0
Name:Mary Anne 
Age:21
Designation:Software Engineer 
Salary:500.0