This question already has answers here:
What does "Could not find or load main class" mean?
(61 answers)
Closed 4 years ago.
Hi i've compile this java project. This is my first project of hello world but when i try to run it on cmd i have this error. Can you help me?
This is my code:
public class CiaoMondo {
public static void main(String[] args)
{
// Prints "Hello, World" to the terminal window.
System.out.println("Hello, World");
}
}
This is the error:
A ClassNotFoundException can be caused for several reasons. The most common (in my experience) are because the java ClassName command is blocked by your firewall, or the file your class is in is improperly named.
Related
This question already has answers here:
InvalidModuleDescriptorException when running my first java app
(8 answers)
Closed 2 years ago.
Entered code when followed through tutorial.
public class HelloWorld {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("test");
}
}
This is the outcome of my code
Error occurred during initialization of boot layer
java.lang.module.FindException: Error reading module: C:\Users\me\Desktop\CIS129\Eclipse files\HelloWorld\bin
Caused by: java.lang.module.InvalidModuleDescriptorException: HelloWorld.class found in top-level directory (unnamed package not allowed in module)
Deleting module-info.java might solve it. If it doesn't, then try creating a package and putting your code in that. Eclipse's interface should help a lot with the process of making a new package.
This question already has an answer here:
Why does my first Hello World Java program give an error on Visual Studio when using System.out to print to screen? [duplicate]
(1 answer)
Closed 2 years ago.
File name: Hello world
public class HelloWorld{
public static void main(String[] args){
String message = "Hello world";
System.out.println(message.toUpperCase());
}
}
And it should work but its says
Replace this use of System.out or System.err by a logger.
I'm using Visual Studio Code and I can't figure out why its not working. Did I do something wrong with setting up VS code?
Thanks
This is a common beginner mistake.
Your code is alright, you just need to fix the filename. Match the filename with the public class declared. Java needs the public class to be named the same as the filename. Fixing that should fix your error.
Name the file HelloWorld and you are good to go.
This question already has answers here:
What does "Could not find or load main class" mean?
(61 answers)
Closed 3 years ago.
Is it because of environment variables? I am getting the following messages.
C:\Users\Manas Sharma\Desktop\java>javac fjp.java
C:\Users\Manas Sharma\Desktop\java>java fjp.class Error: Could not
find or load main class fjp.class
import java.lang.*;
class fjp{
public static void main (String[] args) {
System.out.println("Hello World");
}
}
You can use
java -classpath . fjp
This question already has answers here:
Could not find or load main class package.class
(3 answers)
Closed 7 years ago.
I have a java project with main class
in this path:
C:\Users\tomer_000\Desktop\eclipse_tmp\
I have followed this tutorial
C:\Users\tomer_000\Desktop\eclipse_tmp\src\tomer1>javac Test.java
I have checked and there are now two files:
Test.java, Test.class
I now try to run:
C:\Users\tomer_000\Desktop\eclipse_tmp\src\tomer1>java Test
and get this error:
Error: couldn't find or load main class Test
I have defined PATH and CLASSPATH on my win8.
I have tried:
PS C:\Users\tomer_000\Desktop\eclipse_tmp\src\tomer1> java tomer1.Test
Error: Could not find or load main class tomer1.Test
how can i fix this?
this is my code:
package tomer1;
public class Test {
public static void main(String[] args) {
System.out.print("hi");
}
}
Go one dir up and run java with a package name:
C:\Users\tomer_000\Desktop\eclipse_tmp\src>java tomer1.Test.java
This question already has answers here:
How can you run a Java program without main method? [duplicate]
(4 answers)
Closed 8 years ago.
Is it possible to run a java program without main method ?
How can I execute this Java program in eclipse?
public class A {
static {
System.out.println("hello");
System.exit(0);
}
}
There are some ways to "run a Java program" without main method.
For example:
you could create a jUnit test. In that case Eclipse will offer you the option "Run as jUnit Test".
you can create a class which extends JApplet. In that case Eclipse will offer the option "Run as Java Applet".
Your question is copied from here, but the answer is :
Use a static initializer block to print the message. This way, as soon as your class is loaded the message will be printed. The trick then becomes using another program to load your class.
public class Hello {
static {
System.out.println("Hello, World!");
}
}
Of course, you can run the program as java Hello and you will see the message; however, the command will also fail with a message stating:
Exception in thread "main" java.lang.NoSuchMethodError: main
or
public class X { static {
System.out.println("Main not required to print this");
System.exit(0);
}}
Run from the cmdline with java X.