My helloworld program is not working when i reopen it in Jcreator

Question

When i create a new class file , or a new project and then a class file, my HelloWorld program always works. It compiles and runs printing the expected result "Hello world"

Then if i close my Jcreator program and double click on my helloworld program to open it again on Jcreator and try to run it instead of getting the same results i get this:

Usage: java [-options] class [args...]
          (to execute a class)
    or  java [-options] -jar jarfile [args...]
       (to execute a jar file)
where options include:
-d32      use a 32-bit data model if available
-d64      use a 64-bit data model if available
-client   to select the "client" VM
-server   to select the "server" VM
-hotspot      is a synonym for the "client" VM  [deprecated]
              The default VM is client.

-cp <class search path of directories and zip/jar files>
-classpath <class search path of directories and zip/jar files>
              A ; separated list of directories, JAR archives,
              and ZIP archives to search for class files.
-D<name>=<value>
              set a system property
-verbose:[class|gc|jni]
              enable verbose output
-version      print product version and exit
-version:<value>
              require the specified version to run
-showversion  print product version and continue
-jre-restrict-search | -no-jre-restrict-search
              include/exclude user private JREs in the version search
-? -help      print this help message
-X            print help on non-standard options
-ea[:<packagename>...|:<classname>]
-enableassertions[:<packagename>...|:<classname>]
              enable assertions with specified granularity
-da[:<packagename>...|:<classname>]
-disableassertions[:<packagename>...|:<classname>]
              disable assertions with specified granularity
-esa | -enablesystemassertions
              enable system assertions
-dsa | -disablesystemassertions
              disable system assertions
-agentlib:<libname>[=<options>]
              load native agent library <libname>, e.g. -agentlib:hprof
              see also, -agentlib:jdwp=help and -agentlib:hprof=help
-agentpath:<pathname>[=<options>]
              load native agent library by full pathname
-javaagent:<jarpath>[=<options>]
              load Java programming language agent, see java.lang.instrument
-splash:<imagepath>
              show splash screen with specified image

See http://www.oracle.com/technetwork/java/javase/documentation/index.html for more details.

Can you please explain me why is this happening ? Its embarrassing not be able to make this work.

Thanks.

PS. there is nothing wrong in my code , i get no errors when i compile the file

Answer 1

The reason it doesn't work is because you are only using a single class file to run. Since that cannot be executed directly, what you need to do when you finish the program is to EXPORT THE ENTIRE FILE. That is what you can use to run, not just a single class.