My problem is that I can compile a java HelloWorld program using javac HelloWorld.java but I cannot run the program using java HelloWorld. I didn't create the code it was developed by a professional programmer. My assignment is to compile and run, so that I see the output.
View RepliesI'm new to this java stuff and when I go to notepad++ and this keeps coming up when I try to compile it: "Error: Could not find or load main class HelloWorld" what it means...
View Replies View RelatedI have a problem that happens randomly where i try to compile and it just comes up with error
"Error: Could not find or load main class com.productiontrackingscreens.rexam.EmployeeAddressList"
This is a program that worked fine until i started it today. Seems a bug with eclipse.
I'm trying to run a java program from cmd. I'm using Windows 8, java version "1.8_0_20". I've got two classes, the main class called Middleware and a secondary class, called WorkerThread, of which the main class is using functions. I've successfully compiled both .java files with javac, and created the .class file. So all files are in the same folder. However, when I attempt to run the main class with java Middleware, I get the error message: "Error: Could not find or load main class". Here's the main class:
package middleware;
import java.net.*;
import java.util.concurrent.*;
public class Middleware {
//Number of threads serving clients.
private static int nr_threads = 5;
private static int portNr = 6789;
private static ServerSocket welcomeSocket;
private static ExecutorService executor;
[code]....
My code compiles and runs fine in eclipse but on the console, I'm having troubles.
I'm getting an error trying to run a welcome app from a book. I've looked at the FAQs and can't seem to solve the issue. I'm guessing my path and/or classpath are not right. Here's my path environment variable.
C:jdk1.8.0_20in;C:ProgramDataOracleJavajavapath;C:Program Files (x86)NVIDIA CorporationPhysXCommon;C:Program Files (x86)InteliCLS Client;C:Program FilesInteliCLS Client;%SystemRoot%system32;%SystemRoot%;%SystemRoot%System32Wbem;%SYSTEMROOT%System32WindowsPowerSh
[Code] ....
Here's my output.
09/01/2014 10:23 PM 634 Welcome.class
09/01/2014 10:21 PM 422 Welcome.java
14 File(s) 126,243,703 bytes
9 Dir(s) 53,942,079,488 bytes free
[Code] .....
It looks like the version command gives me what it should, so it appears I've got java setup right, but I"m stuck on the error I'm getting :
C:jdk1.8.0_20>javac -version
javac 1.8.0_20
C:jdk1.8.0_20>
I was trying to write my own version of the game SimpleDotCom from Head First Java. I have two files:
Game.java:
package project_01;
public class Game{
byte hitCount = 0;
String result = "miss";
int counter = 0;
String checkGuess(int[] location,int userGuess){
[Code] .....
The two files are in the same directory, "project_01" and the CLASSPATH environment variable is set to ".;".
The game compiled but when I tried launching it with "java GameTester" it returned the error : Could not find or load main class GameTester. I know my game is horrible and probably extremely buggy but I'll fix all the bugs, etc. later, right now I just need to get it to run.
I have permanently set the path of bin of JDK 1.6 in the environment variables of my system. I am able to compile any of my java programs successfully. But when I give command to run the program I am getting an error "could not find or load main class".
When I write the command "set classpath=.;" program runs successfully. I want to know whether I have to set this classpath everytime I run a new progaram. Is there any permanent way to set classpath ?
I creates this simple code (shown below) inside a package of a major opensource code (i.e., openSHA), but when i run it the following error appears. The error mentions a class named "KT_testGmpeForScenarioRupture" that i wrote before and did not run showing exactly the same error.
Code:
package org.opensha.sha.gcim.imr.attenRelImpl;
public class KT_Test {
private static void main(String args) {
int x=4;
System.out.println("x is " + x);
}
}
Error: Could not find or load main class org.opensha.sha.gcim.imr.attenRelImpl.KT_testGmpeF orScenarioRupture
I am using Netbeans as my IDE and I have created a program called Saluton.java
I navigate to the folder holding the class file using the command line under Windows 7 but when I issue the command java Saluton.class I get an error it cannot load or find the main class.
I tried running my program on cmd but it produces the error "could not find or load main class" ...It compiles well but it just doesn't run. Here is my code:
package writedoc;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.io.IOException;
public class WriteDoc {
public static void main(String[] args) throws IOException {
String strDocument="grades.txt";
[Code] ....
i have a run time error that could not find or load the main file java .
View Replies View RelatedCould not find or load the main class.
package in.javadigest.encryption;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.security.KeyPair;
[Code] ....
Its compiling the compiled class is in C:programsclass folder. Iam running the program using the following commands...
javac MainClass2.java // This is working fine
java -cp C:programsclass MainClass2
I've just started, so right now I'm reading about declaring enums, the book lists the following code
enum CoffeeSize {
//8,10 & 16 are passed to the constuctor
BIG(6), HUGE(10), OVERWHELMING(16);
CoffeeSize(int ounces){ //constructor
this.ounces = ounces;
[Code] .....
I'm assuming that code to be in a same file since enums can be declared within and outside a class, so I saved it into a file named "Coffee.java", it compiles just fine from command line but when I try to execute "java Coffee" it throws "Error: Could not find or load main class Coffee"...
When I try to run Java from the Windows DOS command line, I'm running into trouble:
1. When I run Java from the wrong directory, I get the error Error: cannot find or load main class myapp1.
2. When I get to the "right" directory (.../MyApp1/build/classes/myapp1/, which is where the MyApp1.class file resides), I get the following error:
Exception in thread "main" java.lang.NoClassDefFoundError: MyApp1 (wrong name: myapp1/MyApp1)
1. The CLASSPATH variable is not set (when I type echo %CLASSPATH% the system returns %CLASSPATH%).
2. I also get the same error above when I use: > java -cp . myapp1
3. I've made sure the PATH is set correctly in environment variables, with the Java path at the beginning of the path string).
I made a breakout like game that runs as a applet and now i wanted to make it run in a jframe so i wrote this
Java Code:
import java.applet.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
public class BrickBuster{
public static void main(String[] args){
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
JApplet BrickBuster = new JApplet();
frame.add(BrickBuster);
BrickBuster.init();
}
} mh_sh_highlight_all('java');
It compiles fine but whenever i try running it with the java command it says it couldnt find or load main class. also i have it save in a folder called BrickBuster so i called java BrickBusterBrickBuster.class
I currently use Eclipse to maintain our Java application. I recently upgraded from Java 6 to Java 7. I updated my Eclipse projects to use the Java 7 .jar files. I can run the application from Eclipse via the Run Configuration.
I can also run the Ant build and it completes successfully. When I install the application on my desktop, I receive the "Java Virtual Machine Launcher: Could not find main class..." error. My CLASSPATH is set to ".".
I am trying to understand how package(directory structure) and JAR files work interchangeably. From my understanding JAR is a package file format typically used to aggregate many Java classes. Since many classes are usually contained inside a package, I should be able to create a JAR file from a package, and use them interchangeably. A single JAR file is easier to handle then multiple classes and folders.
To test my understanding of the concept, I am working with the following project structure,
/development_directory
____/BookPackage
________Book.java
____BookDemo.java
Book.java contains the following code,
package BookPackage;
public class Book{
private String bookname;
public Book(String str){
bookname = str;
}
public String getBookName(){
return bookname;
}
}
and BookDemo.java contains the following code,
import BookPackage.Book;
class BookDemo{
public static void main(String ... args){
Book b = new Book("Lord of the Rings");
System.out.println(b.getBookName());
}
}
From the development_directory, I used the following commands to compile and run the project,
development_directory/ javac BookDemo.java
development_directory/ java BookDemo
...and it compiles and works as expected.Now, I will try to convert the BookPackage folder(package) into single jar file for portability, and I am using the following command to do that,development_directory/ jar -cf bookpkg.jar BookPackage ...this command generates the bookpkg.jar file.
I am going to remove the BookPackage folder to see if bookpkg.jar file really works as a replacement for the BookPackage directory structure.
After removal of BookPackage folder, the development_directory structure looks like this,
/development_directory
____bookpkg.jar
____BookDemo.java
Now, I tried to use the following commands to see if the program works as before,
// to compile
development_directory/ javac -cp ./bookpkg.jar BookDemo.java
...it compiles without any error - this means the replacement of bookpkg.jar for BookPackage(package) folder structure is working - Am I correct?
// to run
development_directory/ java -cp ./bookpkg.jar BookDemo
...And I hit an error,
Error: Could not find or load main class BookDemo
But the BookDemo class is at default namespace - why it JRE won't be able to find the main method?
And, the way I am trying to replace package folder structure with a single JAR file - am I getting the concept correctly?
Whenever I try to write a file to the disk and then load it within the same Class (if it is even possible) ...
It gives me an error: Could not find the main class: score.Score. Program will exit.
I have tried this with 2 different classes and it works fine? Why that error is appearing.
Code:
package score;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.Scanner;
public class Score {
public static void main(String [] args) throws Exception
[Code] .....
I am writing a palindrome program. I don't understand what is wrong with my Main method. It is giving me error and error is "Can not find symbol in main method"
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class PalindromeA extends JFrame {
private JTextField inText;
private JTextField outText;
[Code] ....
I've 3 classes.
1. Circle
2. GetInputFromUser
3. testCircle
package ABC;
public class Circle {
private double radius;
public double getRadius() {
return radius;
[Code] .....
In the testCircle class, in the line: getRadius = ui1.GetInput();
It's showing the error: The method GetInput(float) in the type GetInputFromUser is not applicable for the arguments ()
And when I do: getRadius = ui1.GetInput(rad);
It's showing the error: rad cannot be resolved
This is my first java program,i am using eclipse IDE-----
package day1.example;
public class MyFirstJava {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("hi");
}
}
When i saved it,it shows no error.when i run it then a pop-up says "could not find the main class.the program will exit" and in the console it says---
java.lang.UnsupportedClassVersionError: day1/example/MyFirstJava : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$000(Unknown Source)
[Code] ......
I am trying to put together an encryption/decryption application that will essentially accept a sentence that is submitted, and spit out the encrypted version and then switch it back to the correct sentence. I have been told to nest my information in the class (rather than the main), but am having difficulty actually understanding how to do this. The error that Eclipse is throwing me is also that it "could not find the main class." Here is my code:
import java.util.Arrays;
import java.util.Random;
public class encryptingWords {
public static void main(String[] args) {
final int ALPHASIZE = 26;
final char[] Lalpha =
[Code] .....
I am suddenly facing error messages when launching my eclipse. Below are the eclipse logs:
!SESSION 2014-12-18 15:17:46.415 -----------------------------------------------
eclipse.buildId=M20130204-1200
java.version=1.8.0_25
java.vendor=Oracle Corporation
BootLoader constants: OS=win32, ARCH=x86_64, WS=win32, NL=en_IN
Command-line arguments: -os win32 -ws win32 -arch x86_64
!ENTRY org.eclipse.osgi 4 0 2014-12-18 15:17:48.105
[Code] ....
I have tried downloading and placing org.eclipse.swt-3.1.jar in the plugins folder of my eclipse and also I tried editing eclipse.ini file with below lines
openFile
-vm
C:Program Files (x86)Javajre1.8.0_25injavaw.exe
-vmargs
but nothing worked.
Within my program I allow users to write their own code to be executed. I then save that code in a .java file and then compile. This gives me a .java file and a .class file within the same package in the src folder. However, the compilation process also creates a .class file in the build folder. When the user edits their code and then re-runs it, the .class file in the build folder does not get updated with the new data, but the .class in the src folder does.
What I want to do is to execute the .class file in the src folder and not the build folder. So far I have the following method, but that somehow refers to the .class file in the build folder:
public void runMethod(String packageFilePath, String className){
try{
URI fileURI = new URI("file:/src/uk/learningAid/UserInputs/");
URL url = fileURI.toURL();
URL[] urls = new URL[]{url};
[code]....
I am trying to create a custom tag, but I am getting the error message:
Unable to load tag handler class "com.tutorialspoint.HelloTag" for tag "ex:Hello"
I am following the steps given in the tutorial: [URL] ....
/Users/s.m/Documents/com/tutorialspoint/HelloTag.java
package com.tutorialspoint;
import javax.servlet.jsp.tagext.*;
import javax.servlet.jsp.*;
import java.io.*;
public class HelloTag extends SimpleTagSupport {
[Code] ....
I am running under MAC system. What could be wrong?
I have created a blackjack playing Lego NXT robot using the Lejos NXJ playform. I thought it would be great if my robot could respond to voice commands, so I installed sphinx and have the HelloWorld demo up and running in eclipse.All I need my robot to respond to is "Stick" and "Twist". I cant seem to find any tutorials for creating my own recognition program. Am I able to modify the HelloWorld demo code to enable it to recognise "Stick" and "Twist" voice files?.
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