copy AccessToken code of your DropBox API in authAccessToken variable in authDropbox() function  
in UploadServlet.java file
copy dropBoxAppKey
copy dropBoxAppSecret
add the following jar in lib of WEB-INF of WebContent
commons-fileupload-1.2.2.jar
commons-io-2.3.jar
dropbox-core-sdk-1.8.2.jar
jackson-core-2.6.1.jar
run the upload.jsp page in WebContent of project using Apache Tomcat server