Problem running a Jar file

Question

I\'ve compiled a java project into a Jar file, and am having issues running it.

When I run:

java -jar myJar.jar

I get the following err

Answer 1

You should specify your main class during jar creation with full path, something like:

<target name="jar" depends="compile">
     <delete file="myJar.jar"/>
     <delete file="MANIFEST.MF"/>
     <manifest file="MANIFEST.MF">
        <attribute name="Main-Class" value="my.package.myClass"/>
    </manifest>

    <jar destfile="myJar.jar"
           basedir="."
           includes="**/*.class"
           manifest="MANIFEST.MF" />
</target>

Answer 2

In your manifest file, make sure you have the attribute Main-Class set to the name of the class containing your main() method. For example, if the package-qualified name of the class is my.cool.Class, then, in your JAR manifest, Main-Class should be set to my.cool.Class.

Also made sure that you have a package declaration in your .java files (for example, in Class.java, make sure you have the proper package my.cool; declaration). Also, make sure your directory hierarchy is set up correctly (my.cool.Class should be in $SRC/my/cool/Class.java).