When i'm trying to run in Eclipse program which has no main method as Java Application it always requires a main method to define. Could anybody please explain is there any simpler way to make configuration run without implementing
public static void main(String[] args) {
}
Every program requires a main method.
The public static void main(String args[]) starts the main thread which your program will run on.
There's more information available here.
You need a main method to run your program.
public static void main(String[] args){
YourClass newObject = new YourClass();
}
Put this method in your class (replace YourClass with your existing class) and hit the run button.
run in Eclipse program which has no main method
NO.You won't be able to run a class by using IDE like Eclipse or anything else. Even you won't be able to run your java program by using Java command from your command prompt, until your java program has public static void main(String args[]) method on it. If you try to run, you will get below mentioned error
Error: Main method not found in class Test, please define the main
method as: public static void main(String[] args)
But you should also know that, we can run a Java program without main method on managed environment like the case of Applet, Servlet and MIDlet. There are actually different types of execution model available in Java, for example Applets which run on browser doesn't have main method. Servlet is also java program, which runs in a Servlet container and since Servlet is also a Java program, we can say that it runs without main method. Third one on this category is MIDlet, which runs on mobile devices.
Related
How to launch a program in psvm with one command?
How does the application know which class to launch first?
I know that psvm should only have starting command and nothing more.
Could you explain this to me?
I mean how to create proper public static void main(String[] args) in a simple program on Maven. Should I create a class i.e. Starter with method run (with sequence actions) and in psvm write new Starter().run()?
psvm stands for public static void main as shown below:
public static void main(String[] args) {
// Your code here
}
psvm is not a standard Java terminology. You can call it as a Java slang. It is the entry point in your standalone Java application i.e. when you run an executable jar, it will execute the class having psvm. There are so much of content about it on the internet e.g. https://dzone.com/articles/executable-java-applications
The main() is the first entry point of Java application. Java Virtual Machine is told to run an application by specifying its class using the application launcher & it will look for the main() with exact syntax of public static void main(String[]).
Considering your comments you want to do something like this :
public class Starter{
public static void main(String args) {
new Starter().run();
}
public void run() {
//your logic
}
}
once you write this,
you have multiple options to run this I am mentioning a few
1) by building jar and then executing that jar using java -jar command
2) or by executing maven command once you have compiled your program using mvn compile, mvn exec:java -Dexec.mainClass="complete name of your main class i.e including package name."
a few links
http://www.vineetmanohar.com/2009/11/3-ways-to-run-java-main-from-maven/
https://www.oracle.com/webfolder/technetwork/tutorials/obe/java/Maven_SE/Maven.html
hope this might help
I'm learning java and practicing on sololearn.com and I copied one of the examples to practice typing code. However the code here -
//Create myClass
class Loader extends Thread {
public static void main(String[] args) {
}
public void run(){
System.out.println("Hello Young World");
}
}
public class MyClass {
public static void main(String[] args) {
Loader obj = new Loader();
obj.start();
}
}
isn't printing "Hello Young World" to my console. In fact I had to add a 'main()' method to the Loader class just to run MyClass.java. However in the example their code ran without having to include a main method in Loader. Maybe they have customized their environment to allow for this type coding and IntelliJ just has different rules. Please could someone copy the code on their machines and run it with IntelliJ to see if they run into the same problem?
I've troubleshooted, but the code seems to be solid.
I guess you start the wrong main-method (the main from the Loader class which is empty). As you noted, you don´t have to add a main-method in your Loader class. Please remove the method and start the main-method from MyClass.
If you have several main-methods, you can choose which one should be executed in the run configurations. In your example, it should look like this:
In this case, make sure you select the one you like to execute.
Another way to execute the right main-method, is to select the class which contains the main-method and hit the play button on the left side:
To run the program in my console I had to 'java MyClass' rather than running 'java MyClass.java' which executed the whole file rather than just the class whose main method I wanted to call!
To run the program in IntelliJ I had to make sure that the right Class was being called as pointed out above.
Notice that the run option for the main class is greyed out. I tried restarting intelliJ, rebuilding, cleaning, everything.
(click to zoom in)
Move your code inside of the src folder. Once it's there, it'll be compiled on-the-fly every time it's saved.
IntelliJ only recognizes files in specific locations as part of the project - namely, anything inside of a blue folder is specifically considered to be source code.
Also - while I can't see all of your source code - be sure that it's proper Java syntax, with a class declared the same as the file and that it has a main method (specifically public static void main(String[] args)). IntelliJ won't run code without a main method (rather, it can't - neither it nor Java would know where to start).
Use
public static void main(String[] args))
Your main method requires a String array or varargs argument to be picked up.
Correct your main() method, from:
public static void main() {...}
to
public static void main(String[] args) {...}
I have a robocode.jar to extend,and then i want to run it from shell.
I can't run it from shell because i get the following error
error: Main method not found in class tema1, please define the main method as:
public static void main(String[] args)
or a JavaFX application class must extend javafx.application.Application
I've searched ,but no answer helped me.
This is my script:
#!/bin/bash
javac -cp robocode.jar: tema1.java
java -cp robocode.jar: tema1
My class it's extendig their class and I have to make it work in the game.
http://robocode.sourceforge.net/
When I run it from Eclipse it's working fine,the game starts,but from shell it's not working
Can someone help me figure out what i have to do to make it work from shell and not only from ide?
Like the error says, you'll have to define a static method main in your class tema1 as follows:
public static void main(String[] args) {
/* your main program */
}
The main method is where your program execution starts.
I have Eclipse Galileo. I created a new Java project but couldn't run the application. I get the following launch error:
Selection does not contain a main type
Change the method signature to
public static void main(String[] args)
and retry.
The signature of the main method is shown below:
public static void main(String[] args)
Also, the following link may be beneficial for you:
http://download.oracle.com/javase/tutorial/getStarted/application/index.html
Nothing wrong with your environment, there really is no entry point to your project. The main method in the screenshot does not have the String[] args parameter. This is not C/C#/C++. You have to specify the String[] args no matter if you use them or not.