Automatically generate java code examples of constructor methods

This article mainly introduces relevant information about the detailed explanation of the automatically generated constructor method in Java. Friends who need it can refer to

Detailed explanation of the automatically generated constructor method in Java

Each class will automatically generate a constructor without parameters without declaring a constructor. If the class declares a constructor, it will not be generated. The proof is as follows:

Example 1:

class person 
{ 
  person(){System.out.println("父类-person");} 
  person(int z){} 
} 
class student extends person 
{ 
// student(int x ,int y){super(8);} 
} 
 
class Rt 
{ 
  public static void main(String[]args) 
  { 
    student student_dx=new student();//创建student类的对象 
  } 
} 
//输出结果:父类-person

Example 2:

class person 
{ 
  person(){System.out.println("父类-person");} 
  person(int z){} 
} 
class student extends person 
{ 
  student(int x ,int y){super(8);} 
} 
 
class Rt 
{ 
  public static void main(String[]args) 
  { 
    student student_dx=new student(3,4);//创建student类的对象 
  } 
} 
//没有输出结果

Example 1 description: The student class automatically generates student() {super();} (provided that the student class does not declare a constructor) Next) 'super()' is used to call the constructor of the parent class.

The person() method in Example 2 was not called, indicating that the student class did not generate student(){super() ;} method. This is because the student class has declared a constructor, and the default constructor without parameters will not be generated.

Another example:

class person 
{ 
  person(int z){} 
} 
class student extends person 
{ 
 
} 
 
class Rt 
{ 
  public static void main(String[]args) 
  { 
    student student_dx=new student();//创建student类的对象 
  } 
} 
/*报错: 
exercise14.java:8: 找不到符号 
符号： 构造函数 person() 
位置： 类 person 
class student extends person 
^ 
1 错误 
*/

Explanation: student The class automatically generates a student(){super();}, but since the person class has declared a constructor, the default constructor with parameters is not generated. Therefore, the error report states that the constructor person() cannot be found.

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