۵ راه مختلف برای ساختن اشیا در جاوا

Employee emp1 = new Employee();

 0: new           #19          // class org/programming/mitra/exercises/Employee  3: dup  4: invokespecial #21          // Method org/programming/mitra/exercises/Employee."":()V

Employee emp2 = (Employee) Class.forName("org.programming.mitra.exercises.Employee").newInstance(); 

Employee emp2 = Employee.class.newInstance();

51: invokevirtual    #70    // Method java/lang/Class.newInstance:()Ljava/lang/Object;

Constructor<Employee> constructor = Employee.class.getConstructor(); Employee emp3 = constructor.newInstance();

111: invokevirtual  #80  // Method java/lang/reflect/Constructor.newInstance:([Ljava/lang/Object;)Ljava/lang/Object;

Employee emp4 = (Employee) emp3.clone();

162: invokevirtual #87  // Method org/programming/mitra/exercises/Employee.clone ()Ljava/lang/Object;

ObjectInputStream in = new ObjectInputStream(new FileInputStream("data.obj")); Employee emp5 = (Employee) in.readObject();

 261: invokevirtual #118 // Method java/io/ObjectInputStream.readObject:()Ljava/lang/Object;

class Employee implements Cloneable, Serializable {     private static final long serialVersionUID = 1L;     private String name;     public Employee() {         System.out.println("Employee Constructor Called...");     }     public String getName() {         return name;     }     public void setName(String name) {         this.name = name;     }     @Override     public int hashCode() {         final int prime = 31;         int result = 1;         result = prime * result + ((name == null) ? 0 : name.hashCode());         return result;     }     @Override     public boolean equals(Object obj) {         if (this == obj)             return true;         if (obj == null)             return false;         if (getClass() != obj.getClass())             return false;         Employee other = (Employee) obj;         if (name == null) {             if (other.name != null)                 return false;         } else if (!name.equals(other.name))             return false;         return true;     }     @Override     public String toString() {         return "Employee [name=" + name + "]";     }     @Override     public Object clone() {         Object obj = null;         try {             obj = super.clone();         } catch (CloneNotSupportedException e) {             e.printStackTrace();         }         return obj;     } }

ublic class ObjectCreation {     public static void main(String... args) throws Exception {         // By using new keyword         Employee emp1 = new Employee();         emp1.setName("Naresh");         System.out.println(emp1 + ", hashcode : " + emp1.hashCode());         // By using Class class's newInstance() method         Employee emp2 = (Employee) Class.forName("org.programming.mitra.exercises.Employee")                                .newInstance();         // Or we can simply do this         // Employee emp2 = Employee.class.newInstance();         emp2.setName("Rishi");         System.out.println(emp2 + ", hashcode : " + emp2.hashCode());         // By using Constructor class's newInstance() method         Constructor<Employee> constructor = Employee.class.getConstructor();         Employee emp3 = constructor.newInstance();         emp3.setName("Yogesh");         System.out.println(emp3 + ", hashcode : " + emp3.hashCode());         // By using clone() method         Employee emp4 = (Employee) emp3.clone();         emp4.setName("Atul");         System.out.println(emp4 + ", hashcode : " + emp4.hashCode());         // By using Deserialization         // Serialization         ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("data.obj"));         out.writeObject(emp4);         out.close();         //Deserialization         ObjectInputStream in = new ObjectInputStream(new FileInputStream("data.obj"));         Employee emp5 = (Employee) in.readObject();         in.close();         emp5.setName("Akash");         System.out.println(emp5 + ", hashcode : " + emp5.hashCode());     } }

Employee Constructor Called... Employee [name=Naresh], hashcode : -1968815046 Employee Constructor Called... Employee [name=Rishi], hashcode : 78970652 Employee Constructor Called... Employee [name=Yogesh], hashcode : -1641292792 Employee [name=Atul], hashcode : 2051657 Employee [name=Akash], hashcode : 63313419