java web copy image in File WebContent

I am a bit new in java I am creating a small page where I receive images in base64, I decode them and I publish them so that they are published by url. For that there exists a folder / webContent / img but it gives me an error

@Path("/get")
public class ServiceGet extends HttpServlet {

  @GET
  @Path("/courses")
  @Produces({ MediaType.APPLICATION_JSON})
  public String courses() throws IOException {
    File file = new File("//home/luiggi/Documentos/eclipse/fotos/EDUARDO_0.jpg");
    FileInputStream imageInFile = new FileInputStream(file);
    byte imageData[] = new byte[(int) file.length()];
    imageInFile.read(imageData);
    String imageDataString = encodeImage(imageData);

    byte[] imageByteArray = decodeImage(imageDataString);
    File f = new File("../../WebContent/img/water-drop-after-convert.jpg");
    FileOutputStream imageOutFile = new FileOutputStream(f);
    imageOutFile.write(imageByteArray);
    imageOutFile.close();

    return "1";
}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">
    <display-name>apiface_v1</display-name>
    <listener>
        <description>       Used to cleanup when a session is destroyed</description>
        <display-name>ZK Session cleaner</display-name>
        <listener-class>org.zkoss.zk.ui.http.HttpSessionListener</listener-class>
    </listener>
    <servlet>
        <servlet-name>Jersey</servlet-name>
        <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
        <init-param>
          <param-name>com.sun.jersey.config.property.packages</param-name>
          <param-value>mi.service</param-value>
        </init-param>
        <init-param>
            <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
            <param-value>true</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet>
        <description>   The ZK loader for ZUML pages</description>
        <servlet-name>zkLoader</servlet-name>
        <servlet-class>org.zkoss.zk.ui.http.DHtmlLayoutServlet</servlet-class>
        <init-param>
          <param-name>update-uri</param-name>
          <param-value>/zkau</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet>
        <description>   The asynchronous update engine for ZK</description>
        <servlet-name>auEngine</servlet-name>
        <servlet-class>org.zkoss.zk.au.http.DHtmlUpdateServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>Jersey</servlet-name>
        <url-pattern>/rest/*</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>zkLoader</servlet-name>
        <url-pattern>*.zul</url-pattern>  
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>zkLoader</servlet-name>
        <url-pattern>*.zhtml</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>auEngine</servlet-name>
        <url-pattern>/zkau/*</url-pattern>
    </servlet-mapping>
    <welcome-file-list>
        <welcome-file>index.zul</welcome-file>
    </welcome-file-list>
</web-app>