1. Make a build.xml file like as follows:

<?xml version="1.0" encoding="UTF-8"?>
<project name="HelloWorld" default="hello">
    <target name="hello">
        <echo>Hello World!</echo>
    </target>
     
    <target name="myTarget">
        <echo>My target executed</echo>
    </target>
</project>

2. Download a jar file used for executing the Ant file named “ant.jar”
Made a java method to execute the ant task:

 /**
     * To execute a target specified in the Ant build.xml file
     * @param buildXmlFileFullPath
     * @param target
     */
    public static boolean executeAntTask(String buildXmlFileFullPath, String target) {
        boolean success = false;
        DefaultLogger consoleLogger = getConsoleLogger();
 
        // Prepare Ant project
        Project project = new Project();
        File buildFile = new File(buildXmlFileFullPath);
        project.setUserProperty("ant.file", buildFile.getAbsolutePath());
        project.addBuildListener(consoleLogger);
 
        // Capture event for Ant script build start / stop / failure
        try {
            project.fireBuildStarted();
            project.init();
            ProjectHelper projectHelper = ProjectHelper.getProjectHelper();
            project.addReference("ant.projectHelper", projectHelper);
            projectHelper.parse(project, buildFile);
             
            // If no target specified then default target will be executed.
            String targetToExecute = (target != null && target.trim().length() > 0) ? target.trim() : project.getDefaultTarget();
            project.executeTarget(targetToExecute);
            project.fireBuildFinished(null);
            success = true;
        } catch (BuildException buildException) {
            project.fireBuildFinished(buildException);
            throw new RuntimeException("!!! Unable to restart the IEHS App !!!", buildException);
        }
         
        return success;
    }

    /**
     * Logger to log output generated while executing ant script in console
     * @return
     */
    private static DefaultLogger getConsoleLogger() {
        DefaultLogger consoleLogger = new DefaultLogger();
        consoleLogger.setErrorPrintStream(System.err);
        consoleLogger.setOutputPrintStream(System.out);
        consoleLogger.setMessageOutputLevel(Project.MSG_INFO);
         
        return consoleLogger;
    }