class First{ public First(){ aMethod(); } public void aMethod(){ System.out.println("in First class"); } } public class Second extends First{ public void aMethod(){ System.out.println("in Second class"); } public static void main(String[] args){ new Second(); } }
时间: 2024-04-21 17:28:39 浏览: 15
这段代码的输出结果是 "in Second class"。因为 Second 类继承了 First 类,并重写了 aMethod() 方法。在创建 Second 类的对象时,会先调用 First 类的构造方法,而 First 类的构造方法中又调用了 aMethod() 方法。由于 Second 类重写了 aMethod() 方法,因此输出结果为 "in Second class"。
相关问题
interface FirstInterface { public void myMethod(); // interface method}interface SecondInterface { public void myOtherMethod(); // interface method}class DemoClass implements FirstInterface, SecondInterface { public void myMethod() { System.out.println("Some text.."); } public void myOtherMethod() { System.out.println("Some other text..."); }}class Main { public static void main(String[] args) { DemoClass myObj = new DemoClass(); myObj.myMethod(); myObj.myOtherMethod(); }}
This code defines two interfaces: `FirstInterface` and `SecondInterface`, each with a single method. The `DemoClass` class implements both interfaces and provides a body for each method.
In the `main` method of the `Main` class, a new `DemoClass` object is created and its `myMethod()` and `myOtherMethod()` methods are called. When the program is run, the output will be:
```
Some text..
Some other text...
```
Note that the output will be printed in two separate lines.
Error: Main method not found in the file, please define the main method as: public static void main(String[] args)
This error message is usually encountered when you try to run a Java program that does not have a main method defined.
In Java, the main method is the entry point of any program, which means that it is the first method that gets executed when you run the program. It is important to have this method defined in your code, otherwise, the Java Virtual Machine (JVM) won't know where to start executing.
To fix this error, you need to define the main method in your code. Here's an example of a simple Java program with a main method:
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, world!");
}
}
In this example, we have defined a class called HelloWorld and a main method that prints out the message "Hello, world!" to the console. When you run this program, the JVM will start executing from the main method and the message will be displayed on the screen.