Latest Articles

Android 'Application not Installed' java.lang.SecurityException [invalid digest for] or [Package ... has no certificates at entry]

07 August 2013

How to solve Android 'Application not Installed' caused by java.lang.SecurityException [invalid digest for] or [Package ... has no certificates at entry] when we sign an Android APK and install it in an Android device.

We sign an Android application (APK) using jarsigner signing tool. While installing the signed APK in an Android device we get the following exception in LogCat: Exception reading res/drawable/[some_... Read more

EJB passivation and activation example

05 August 2013

In this tutorial we will cover Java EE Stateful Session Bean passivation and activation mechanism.

Stateful Session Beans are usually coupled with some given client and - as the name states - they keep state across client invocations.Since a conversation with a client may be long-lived, and many si... Read more

activation ejb java java-ee passivation stateful

Java EE Stateful Session Bean (EJB) example

31 July 2013

In this tutorial we will see how to create a simple Stateful Session Bean (EJB) and use it in a web application context, more precisely a Java Servlet.

Stateful Session Beans - as the name states (and opposite to Stateless Session Beans) - are able to keep state across multiple calls from a given client during an established session.A Stateful EJB is... Read more

ejb java java-ee stateful

Java EE EJB transaction propagation (@TransactionAttribute) tutorial

08 July 2013

In this tutorial we will see the available transaction propagation behaviours provided by the EJB container using @TransactionAttribute annotation.

While dealing with Container Managed Transactions (CMT) in EJB, the application developer is able to declaratively define how an arbitrary call to an EJB method should behave in terms of transaction p... Read more

ejb java java-ee jpa jta tx

Java EE EJB Interceptors tutorial and example

30 June 2013

In this tutorial you will learn how to configure EJB Interceptors used to - as the name states - intercept calls to EJB methods.

Interceptors - as the name states - are components that intercepts calls to EJB methods. They may be used - for example - to implement an auditing / logging system around calls to EJB.Another usage ex... Read more

ejb interceptors java java-ee

Java EE CDI - Inject beans from external (3rd party) libraries example

23 June 2013

In this tutorial we will see how to inject beans from external - or 3d party - libraries in Java EE CDI

When we need an external JAR to be scanned by a Java EE container for CDI beans we must define the JAR as a target for CDI bean scanning, ie. via beans.xml file. What if the JAR is provided by an exte... Read more

cdi java java-ee

Spring JTA multiple resource transactions in Tomcat with Atomikos example

17 June 2013

In this tutorial you will learn how to configure a JTA transaction manager outside an enterprise container - using the Spring framework and Atomikos, both deployed in Tomcat - in order to implement distributed multiple resource (or XA) transactions.

Distributed multiple resource transactions in Java are usually accomplished by resorting to the Java Transaction API (JTA). One usually delegates the task of distributed transaction coordination to an... Read more

atomikos hibernate java jpa jta spring tomcat tx xa

Java EE CDI programmatic dependency disambiguation example - Injection Point inspection

08 June 2013

In this tutorial we will see how to implement Java EE CDI dependency disambiguation in a programmatic (or dynamic) way by inspecting injection points. The same applies for programmatic dependency resolution at runtime.

In Java EE CDI it is possible to provide multiple implementations of a given interface - or service - to the service clients. In this tutorial we will see how to implement a dynamic mechanism for fetc... Read more

cdi java java-ee

About the author

Gonçalo Marques is a Software Engineer with several years of experience in software development and architecture definition. During this period his main focus was delivering software solutions in banking, telecommunications and governmental areas. He created the Bytes Lounge website with one ultimate goal: share his knowledge with the software development community. His main area of expertise is Java and open source.

GitHub profile: https://github.com/gonmarques

He is also the author of the WiFi File Browser Android application: