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Thread: Main class Error

  1. #1
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    Default Main class Error

    Hi, I have got a main class error, may i know what'swrong please?
    // Driver for parser
    package myparser;
     
    import java.io.*;
    import java_cup.runtime.Symbol;
    import static myparser.Main.do_debug_parse;
     
     
     
     
     
    //package myparser;
    //import java_cup.runtime.*;
    class Main {
     
      static boolean do_debug_parse = true;
     
      static public void main(String[] args) throws java.io.IOException {
          File infile = new File("C://Users//ASUS//Documents//NetBeansProjects//myparser_proj//myparser//myparser//input.txt");
         //parser parser_obj = new parser(new Yylex(fin));
          FileInputStream fin = null;
          try
          {
              fin = new FileInputStream(infile);
     
              /* create a parsing object */
              parser parser_obj = new parser(new Yylex(fin));
     
              Symbol parse_tree = null;
              if (do_debug_parse)
                  parse_tree = parser_obj.debug_parse();
              else
                  parse_tree = parser_obj.parse();
              System.out.println("Parse successful");
              fin.close();
          }
          catch(FileNotFoundException e)
          {
              System.out.println("File " + infile.getAbsolutePath() +
                      " could not be found on filesystem");
          }
          catch(IOException ioe)
          {
              System.out.println("Exception while reading the file" + ioe);
          }
          catch (Exception e) {
            /* do cleanup here -- possibly rethrow e */
          } finally {
    	/* do close out here */
          }
      }
    }

    The code compiles fine but the error message is received when the code is run.
    The errors are:
    Exception in thread "main" java.lang.NoClassDefFoundError: myparser/Yylex (wrong name: Yylex)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java :791)
    at java.security.SecureClassLoader.defineClass(Secure ClassLoader.java:142)
    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$1.run(URLClassLoader.java: 355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.j ava:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:4 23)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launche r.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:3 56)
    at myparser.Main.main(Main.java:27)
    Java Result: 1
    BUILD SUCCESSFUL (total time: 2 seconds)


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Main class Error

    Exception in thread "main" java.lang.NoClassDefFoundError: myparser/Yylex (wrong name: Yylex)
    The Yylex class is in a package. The code asked for it without the package name.

    Not sure how this error happened. Were there older versions that were not in the pacakge?
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: Main class Error

    No Sir there weren't any older versions in that package...

    --- Update ---

    But there is file denoted as Yylex.class that was generated in a different folder,I included them but still results in the same error.

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: Main class Error

    What is the classpath when the class is executed? What folder is the Yylex.class file in? Is the Yylex class in a package?
    If you don't understand my answer, don't ignore it, ask a question.

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