Create a runnable jar using ant and genJar

Question

I have written the following ant target:

<target name="approval_request_parser_compile">
        <taskdef resource="genjar.properties" classpath="GenJar.jar"/>
        <genjar jarfile="prod/lib/approvalRequestParser.jar">

            <class>
                <fileset dir=".">
                 <include name="com.bet.Check.class"/>
                    <include name="com.bet.Approve.class"/>
                    <include name="com.bet.CheckText.class"/>
                    <include name="com.bet.Request.class"/>
                    <include name="com.bet.ApprovalRequestParser.class"/> #contains the main method
                </fileset>
            </class>
            <classpath>
                <fileset dir="lib">
                    <include name="*.jar" />
                </fileset>
                <pathelement path="."/>
            </classpath>
        </genjar>
    </target>

The jar is created successfully, but when I go to /prod/lib and I type:

java -jar approvalRequestParser.jar

this error is raised:

no main manifest attribute, in approvalRequestParser.jar

Any ideas?

Answer 1

I am not using genjar but you need to create the manifest file, see an example below

<target name="buildJAR" depends="compile">
  <tstamp>
    <format property="BUILD.TSTAMP" pattern="MMMM dd yyyy hh:mm:ss" locale="en"/>
    </tstamp>
    <buildnumber file="build.number"/>
  <mkdir dir="classes/META-INF"/>
  <echo file="classes/META-INF/version.txt">Version: ${VERSION} (build #: ${build.number}, ${BUILD.TSTAMP})</echo>
    <manifest file="classes/META-INF/MANIFEST.MF">
        <attribute name="Specification-Title" value="ANY TEXT CAN GO HERE"/>
        <attribute name="Specification-Version" value="${VERSION}"/>
        <attribute name="Specification-Vendor" value="COMPANY NAME"/>
        <attribute name="Implementation-Title" value="WHAT CODE DOES"/>
        <attribute name="Implementation-Version" value="${VERSION} (build #: ${build.number}, ${BUILD.TSTAMP})"/> 
        <attribute name="Implementation-Vendor" value="WHO DOES IT"/>
    </manifest>
  <jar destfile="JAR FILE" basedir="classes" 
       includes="${CORE_CODE}" manifest="classes/META-INF/MANIFEST.MF"/>
</target>

I think you can apply the same for genjar task