java-内部类说明

public class Printer{
    public void print() {
        System.out.println("this is PrintClass.");
    }
}

public class testClass {
    public static void main(String[] args) throws Exception {
        Printer printer1 = new Printer();
        Printer printer2 = getPrinter();
  
        printer1.print();//output:this is PrintClass.
        printer2.print();//this is testClass.
    }
 
    public Printer getPrinter() {
        return new Printer() {
            public void print() {
                System.out.println("this is testClass.");
            }
        };
     }
}