使用cmd运行时java.lang.NoClassDefFoundError

Question

I have some problems testing a program from a java programming book. I wrote the code in eclipse and succeded running it, but when I compile the .java file via the command line and then run it with java ConsoleEcho , I get this error:

Exception in thread "main" java.lang.NoClassDefFoundError: ConsoleEcho (wrong na
me: einausgabe/ConsoleEcho)
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:792)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:14
2)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
        at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)

The code for my program is:

package einausgabe;

import java.io.IOException;
import static java.lang.System.*;

public class ConsoleEcho {
    public static void main( String args[] ) throws IOException {
        while( true ) {
            int code = in.read();
            out.write(code);
        }
    }
}

The commands I used are:

javac ConsoleEcho
java ConsoleEcho

I run this from the directory ..\\Java\\ProgrammierenMitJava2\\src\\einausgabe

I don't get any errors by compiling. Tried java einausgabe.ConsoleEcho and then I get this error message:

Error: Could not find or load main class einausgabe.ConsoleEcho

Answer 1

You need to include the package name in the command line, something like:

java einausgabe.ConsoleEcho

you appear to just have the class name in your command.

Answer 2

It seems that you forgot the package name

Use

java einausgabe.ConsoleEcho