Certainly! Here’s a simple "Hello, World!" program in Java:

```java
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}
```

### Explanation:

1. **public class HelloWorld**: This line defines a public class named `HelloWorld`. In Java, every application must have at least one class definition.

2. **public static void main(String[] args)**: This is the main method, which is the entry point of any Java application. The JVM (Java Virtual Machine) calls this method to start the execution of the program.

3. **System.out.println("Hello, World!");**: This line prints "Hello, World!" to the console. `System.out` is a predefined output stream in Java.

### How to Run the Program:

1. **Save the Code**: Save the above code in a file named `HelloWorld.java`.

2. **Compile the Program**: Open your command line, navigate to the directory where you saved the file, and run:
```
javac HelloWorld.java
```

3. **Run the Program**: After compilation, run the program with:
```
java HelloWorld
```

You should see the output:
```
Hello, World!
```
----------------
下面是广告：
想在Toronto买卖房吗？请联系微信 tonyzhucn
----------------
现在这里做广告吗?请联系微信 tonyzhu668