How to identify data types during runtime in Java

1. The getClasses() method of the Class object obtains all the public internal classes in the class, as well as the internal classes inherited from the parent class and parent interface. The getinterfaces() method returns all interfaces inherited by the class.

import javax.print.attribute.standard.PrinterInfo;

interface  HasBatteries{}
interface Waterproof{}
interface ShootsThings{}

class Toy{
    Toy(){}
    Toy(int i){}
}

class FancyToy extends Toy implements HasBatteries,Waterproof,ShootsThings{
    public FancyToy() {
        // TODO 自动生成的构造函数存根
        super(1);
    }
}

public class ToyTest {
    public static void main(String[] args){
        Class class1=null;
        try{
            class1=class1.forName("FancyToy");
        }catch (ClassNotFoundException e) {
            // TODO: handle exception
        }
        printInfo(class1);
        Class[] faces=class1.getInterfaces();
        for(int i=0;i<faces.length;i++){
            printInfo(faces[i]);
        }
        Class cy=class1.getSuperclass();
        Object cObject=null;
        try{
            cObject=cy.newInstance();
        }catch (Exception e) {
            // TODO: handle exception
        }
        printInfo(cObject.getClass());
        
    }
    
    static void printInfo(Class cc){
        System.out.println("Class name:"+cc.getName()+" is interface? "+cc.isInterface());
    }

}

2. When using forName() of the Class object, the classname parameter passed needs the full name. You cannot just add the class name, such as package name.class name, java.lang.String.

import javax.print.attribute.standard.PrinterInfo;

interface  HasBatteries{}
interface Waterproof{}
interface ShootsThings{}

class Toy{
    Toy(){}
    Toy(int i){}
}

class FancyToy extends Toy implements HasBatteries,Waterproof,ShootsThings{
    public FancyToy() {
        // TODO 自动生成的构造函数存根
        super(1);
    }
}

public class ToyTest {
    public static void main(String[] args){
        Class class1=null;
        try{
            class1=class1.forName("FancyToy");
        }catch (ClassNotFoundException e) {
            // TODO: handle exception
        }
        printInfo(class1);
        Class[] faces=class1.getInterfaces();
        for(int i=0;i<faces.length;i++){
            printInfo(faces[i]);
        }
        Class cy=class1.getSuperclass();
        Object cObject=null;
        try{
            cObject=cy.newInstance();
        }catch (Exception e) {
            // TODO: handle exception
        }
        printInfo(cObject.getClass());
        
    }
    
    static void printInfo(Class cc){
        System.out.println("Class name:"+cc.getName()+" is interface? "+cc.isInterface());
    }

}

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