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.
Related
This question already has answers here:
How can a Java program get its own process ID?
(22 answers)
Closed 1 year ago.
I am running a simple Java application as follows:
class MyApp
{
public static void main(String[] args)
{
// Do stuff
}
}
Now I want to get the process ID (PID) of this application from inside my main() function so that I can save it to a file. How can I do that in a platform-independent way?
EDIT: The existing solutions on Stackoverflow are many years old and probably better solutions exist today. This is why I'm asking this question.
EDIT 2: I would prefer solutions that do NOT require Java 9.
My operating environment is jdk6
import java.lang.management.ManagementFactory;
public static void main(String[] args) {
String name = ManagementFactory.getRuntimeMXBean().getName();
System.out.print(name.split("#")[0]);
}
Use RuntimeMXBean
RuntimeMXBean runtime = ManagementFactory.getRuntimeMXBean();
long pid = runtime.getPid();
You can get PID by following
ManagementFactory.getRuntimeMXBean().getSystemProperties().get("PID")
Or
System.getProperty("PID");
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.
This question already has answers here:
How do I run a Java program from the command line on Windows?
(13 answers)
What does "Could not find or load main class" mean?
(61 answers)
Closed 6 years ago.
import java.util.*;
class sample
{
public static void main(String arg[])
{
System.out.println("Here it is!");
}
}
How to resolve this Error? I tried set path="..." and set classpath="..." But nothing helped me. Can you help me?
mabye you can point the system of where the jdk is. to do this on windows 10, search environment variables in the search bar and click on edit the system environment variables. when you open it, click on environment variables.. at the bottom. you should see 2 sections. in the lower section click new. for the name type JAVA_HOME. it is necessary to have caps but dont include the dot. and for the path, put the directory of the java jdk. always put the folder of the latest version.
This happens because filename of the java file is not same as your class name.
In your case file name must be "sample.java".
If you have multiple classes in this file, file name must contains the class that holds the main method.
Make sure you use capital/simple letters correctly.
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.
This question already has answers here:
What does "Could not find or load main class" mean?
(61 answers)
Closed 9 years ago.
Im a java noob. Basically I am trying to create a program that compares two command line arguments while ignoring case and prints out the lesser of the two strings. Here is what I have so far:
public class CompareStrings
{
public static void main(String[] args)
{
String s1 = new String(args[0]);
String s2 = new String(args[1]);
if ( s1.compareToIgnoreCase(s2) > 0 )
System.out.println(s2);
else if ( s1.compareToIgnoreCase(s2) < 0 )
System.out.println(s1);
else
System.out.println("Both strings are equal.");
}
}
I keep getting the error
Error: Could not find or load main class CompareString
when I try to run it. What am I doing wrong?
"Error: Could not find or load main class CompareString"
Your error message says you couldn't load class "CompareString", but your code says your class name is CompareStrings.
Your class name is wrong.
Your error says
Error: Could not find or load main class CompareString
but the name of class is CompareStrings not CompareString
launch using java CompareStrings
Read this good tutorial on compiling and launching java programs
First of all you are trying to use wrong class, should be CompareStrings and not CompareString.
Second, I would recommend using a nice utility lib for handling command line called Cliche from Google Code site
And third, it would be good to check if the given string is null before you call compareToIgnoreCase on it
as per your error i can gues that you are running CompareString but your class is CompareStrings
So either run java CompareStrings or rename your class to CompareString
If this is the only code you have, save that file as CompareStrings.java not CompareString, and in command prompt javac CompareStrings.java. (to do this you need to configure java). then use java CompareStrings abc cbs to run this. and this will give you out put as abc