Thus, we decided to embed a SQLite database in the app. This worked fine as long as I was locally testing the application. However, when deploying to a production Tomcat instance I started getting these exceptions:

java.sql.SQLException: opening db: 'restfulepcis.db': Permission denied
at org.sqlite.Conn. init(Conn.java:117)
at org.sqlite.Conn. init(Conn.java:49)
at org.sqlite.JDBC.connect(JDBC.java:86)

The reason is pretty clear, on the production server I did not have permission to write to the Tomcat working directory.

I was left with two solutions:
1) have the directory where the database has to be created as a config parameter
2) find a directory that’s universally accessible from an app in an app server.
Since 1) involved user-configuration it was not an option.

There is actually a folder to which any Web app can write, the folder where the app is deployed (or at least my knowledge). The location of this folder can be found by calling:


ServletContext context = servletContext.getRealPath("/")


from a servlet. Since my app is a JAX-RS (RESTful) application I can obtain it by CDI (Contexts and Dependency Injection):

@Context
ServletContext servletContext;

/**
* Returns a representation of the EPCIS REST Adapter home resource according to the requested mime type
*
* @param context
* @return an instance of javax.ws.rs.core.Resource
*/
@GET
public Resource getRESTfulEPCIS(@Context UriInfo context) {
System.setProperty("sqlite.system.home", servletContext.getRealPath("/"));
RESTfulEPCISBusinessLogic logic = new RESTfulEPCISBusinessLogic();
return logic.getRESTfulEPCIS(context);
}


I then load the sqlite.system.home from my database manager class (which is not a Servlet) and use it as path in my database connection URI:


...
String sqliteHome = System.getProperty("sqlite.system.home");
...
private Connection getConnection() {
Connection connection = null;
try {
Class.forName(DRIVER);
connection = DriverManager.getConnection("jdbc:sqlite:" + sqliteHome + DB_NAME + ".db");
...


Note that for Apache Derby, you can make it even easier by simply setting the derby.system.home in the servlet class. Then, you do not need to read it manually from your database manager class as it is read automatically when loading the driver:

System.setProperty("derby.system.home", servletContext.getRealPath("/"));


HttpTransportSE androidHttpTransport = new HttpTransportSE(URL);
androidHttpTransport.debug = true;


and get a hold on the raw response from the service using:

String result = androidHttpTransport.responseDump;

sudo update-alternatives --config java

As a result your property file will be copied at the root of your packaged jar.

Run sudo update-java-alternatives -s XXXX to set the XXX java version as default.
For Sun Java 6 this would be sudo update-java-alternatives -s java-6-sun

Run java -version to ensure that the correct version is being called.

Source: https://help.ubuntu.com/community/Java

From Java 1.6.

Thus you were probably quite frustrated when seeing that a GWT (Google Web Toolkit) client cannot send other requests than POST or GET.
Well here is the solution:

public class RequestBuilderForAnyHTTPMethodTypeExample extends RequestBuilder {

/**
* Constructor that allows a developer to override the HTTP method
* restrictions imposed by the RequestBuilder class. Note if you override the
* RequestBuilder's HTTP method restrictions in this manner, your application
* may not work correctly on Safari browsers.
*
* @param httpMethod any non-null, non-empty string is considered valid
* @param url any non-null, non-empty string is considered valid
*
* @throws IllegalArgumentException if httpMethod or url are empty
* @throws NullPointerException if httpMethod or url are null
*/
public RequestBuilderForAnyHTTPMethodTypeExample(String httpMethod, String url) {
super(httpMethod, url);
}


i.e. simply subclass the RequestBuilder

Source: (see the bottom of the page).