Error when compiling java applications from command prompt

Question

Recently, when trying to compile java programs from the command prompt, I get this error:

Error: Cannot find or load main class com.sun.tools.javac.Main

I have the latest versions of the JDK and JRE, and I still get the error. Here is what I type in the command line:

C:\Java_Source_Codes>javac hi.java

Can anyone help?

(Here is my java code)

public class hi{
  public static void main(String[] args){
    System.out.println("hello, world!");
  }
}

Edwin Buck · Accepted Answer · 2012-07-17 16:00:00Z

1

You have a number of issues, Kumar mentioned the compilation issue, but that's not the immediate problem that's stopping you.

You have JAVA_HOME set to a Java Runtime environment, but are finding javac on the system PATH. When this happens, you can call javac from the command line, but when javac detects the JAVA_HOME environmental variable, it loads its libraries from a directory that doesn't include the "java tools", tools.jar. The contents of "java tools" includes the classes that implement the compiler.

You probably have JAVA_HOME set to something like /some/path/here/jre. Assuming that the jre directory is the embedded JRE shipped with your JDK, you probably should have set the JAVA_HOME to /some/path/here.

edited Jul 17, 2012 at 16:00

answered Jul 17, 2012 at 15:52

Edwin Buck

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4 Comments

imulsion Over a year ago

I did that, but now it says that javac is not recognized as an internal or external command, operable program or batch file

Edwin Buck Over a year ago

@user1532256 That's because you either have a PATH entry that uses JAVA_HOME within it, and you didn't update the PATH entry to include the JDK bin directory (odds are is is somewhat mangled to accomodate the wrong JAVA_HOME setting) or because you attempted to follow multiple "suggestions" and managed to set your PATH incorrectly in some other manner.

imulsion Over a year ago

OK... How do I set the JAVA_HOME path? I tried typing it into the cmd, followed by the path, but it just said about the batch file thing again, only this time with JAVA_HOME

Edwin Buck Over a year ago

There is no such thing as a "JAVA_HOME path". There is a JAVA_HOME environmental variable, and a PATH environmental variable. JAVA_HOME should point to the base directory of the installation, and PATH should be set to the same value as JAVA_HOME, with an additional "bin" directory added to it. So if you installed Java in C:\java-1.6.23, then JAVA_HOME should be set to "C:\java-1.6.23" and PATH should contain an entry "C:\java.1.6.23\bin".

ioreskovic · Accepted Answer · 2012-07-17 15:53:36Z

1

You need to have your PATH variable set up with a path to Java tools needed for compilation.

You need to have these folders in Path system variable.

D:\Program Files\Java\jdk1.6.0_32\jre;D:\Program Files\Java\jdk1.6.0_32\bin

Just replace D:\Program Files\Java with the folder you have installed Java on your computer. Also, if you are using any other verion of JDK, replace jdk1.6.0_32 with your own.

edited Jul 17, 2012 at 15:53

answered Jul 17, 2012 at 15:46

ioreskovic

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1 Comment

Edwin Buck Over a year ago

This isn't right, if the path was wrong, then he couldn't access javac. It is that his JAVA_HOME doesn't point to a JDK, it probably points to the embedded JRE within the JDK, hence the ability to call javac and the inability for it to find the tools.jar which contains the compiler implementation.

nate_weldon · Accepted Answer · 2012-07-17 15:46:47Z

0

This is due to some issue with your PATH.

Quick guess is you have multiple version of java on your PATH

answered Jul 17, 2012 at 15:46

nate_weldon

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Comments

Kumar Vivek Mitra · Accepted Answer · 2012-07-17 15:54:05Z

0

Set the Path to the bin directory of the jdk in your system..

Try typing java -version on the cmd to see if your Java path is properly set.

Mine is..

C:\Program Files\Java\jdk1.7.0\bin

edited Jul 17, 2012 at 15:54

answered Jul 17, 2012 at 15:46

Kumar Vivek Mitra

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6 Comments

Lorenz Over a year ago

I guess the problem occurs earlier.

imulsion Over a year ago

Sorry, that was me writing this question! It is the same in my program :)

Kumar Vivek Mitra Over a year ago

The question was with javac HelloWorld.java when it was first posted

Brian Agnew Over a year ago

He's not finding the compiler class, so it's not getting anywhere near a naming convention issue, I'm afraid

imulsion Over a year ago

I tried typing java -version but it came up with 'java' is not recognized as an internal or external command, operable program or batch file

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Shriram · Accepted Answer · 2014-02-14 19:38:43Z

0

I had the similar problem but found a simple solution that might work in your case too.

My problem was I simply made a new folder in c directory to save my *.java files (like a test folder) and set my PATH to ...jdk\bin folder.

When I try to compile in cmd I got the same error main class not found.

So i went to environment variable and in user variable, where I saw my CLASSPATH pointing to same folder. So I changed my CLASSPATH to folder having my files in my case C:\test and the problem was solved.

Hope this helps.

answered Feb 14, 2014 at 19:38

Shriram

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