Default constructors in Java

In Java if no constructors are written in a class, there is an argument-free constructor, as follows:

public class Children {private string Name;private string Address;public string GetName () {return name;} public void SetName (String name) {this.name = name;} Public String getaddress () {return address;} public void setaddress (String address) {this.address = address;}}

The above code is equivalent to the following:

public class Children {private string Name;private string Address;public Children () {}public string getName () {return name ;} public void SetName (String name) {this.name = name;} Public String getaddress () {return address;} public void setaddress (String address) {this.address = address;}}

　　

But if you specify a constructor that has a parameter, the parameterless constructor ceases to exist:

So in the spring configuration, the following configuration is wrong:

  <bean id= "Children"  class= "Com.wc82.Children" >  <property name= "Address"  value= "Stresst" > </property>  <property name= "name" value= "Nick" ></property>  </bean>

The above configuration is similar to the following:

Children c=new Children () C.setname ("Nick"); C.setaddress ("Stresst");

However, the default construction method no longer exists, so it will be an error, can be changed to the following configuration:

  <bean id= "Children"  class= "Com.wc82.Children" >        <constructor-arg  value= "1111"  />        <constructor-arg  value= ""  />  </bean>

　　

Default constructors in Java