I can't run HelloWorld in Eclipse - it shows message:
Error: Main method not found in class com.taksila.javabyexample.overview.HelloWorld, please define the main method as:
public static void main(String[] args)
or a JavaFX application class must extend javafx.application.Application
Here is my code:
package com.taksila.javabyexample.overview;
public class HelloWorld {
public static void main(String[] args){
System.out.println("Hi Planet");
}
}
Code is correct. Try to restart IDE or just save sketch :-)
Yes, your code is definitely correct. Save it, restart the IDE, and wait to load all of its components. Then again run it!
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 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.
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.
import stanford.karel.*;
public class MidpointFindingKarel extends SuperKarel
{
public void run()
{
move();
}
}
This is my example code.the method run() is inherited from the SuperKarel class.
All i want is to run this code and codes like this as a java application.but when i click on the 'Run as', i see only 'run as java applet' there.how to get the option of 'run as java application there'.i know how to create a run configuration but when i do,that configuration is being applicable only to a particular java file.how to run codes like these without creating a run configuration everytime for a new java file??
You need to declare main() as
public static void main(String[] args)
For instance you might change your class to
public class MidpointFindingKarel extends SuperKarel {
public void run() {
move();
}
public static void main(String[] args) {
MidpointFindingKarel mfk = new MidpointFindingKarel();
mfk.run();
}
In order to do that, you need a
public static void main(String[] args) {
}
method in your class. It may be that MidpointFindingKarel is used by the main class which is defined somewhere else. In that case, search for it and run that class.
In essence, Eclipse populates the run menu based on the current class that has focus in the editor.
Once, you have the run configuration set up, you can of course simply right click on the run menu dropdown box and select the class to execute (typically, top-left on the toolbar).
You need to add a main method in your class.
Run as Java Application is applicable only to classes having public static main method. Change the code to add main method. You will find the option of run as.
I run IntelliJ. Simple project and received println in red.
package test;
public class Main {
public static void main(String[] args) {
System.out.println("Console is.");
}
}
Error:
Cannot resolve method 'println'...
I have checked that in module setting JDK is. What another I should check? Thanks.
I needed to re-start IntelliJ after installing it.