Java EE 7 Application Developer case studies
Java EE 7 Application Developer · Put your knowledge to work in context.
The Java EE 7 Application Developer credential (exam code 1Z0-900) is Oracle's professional-level certification for developers who build server-side Java applications on the Java EE 7 platform. It suits working developers who already write Java and now need to prove they can assemble the platform's component model: servlets and JSP, JSF, EJB and CDI, JPA, JAX-RS and JAX-WS services, plus the security, transaction and messaging concerns that cut across them. The Java EE 7 Application Developer case studies are 5 cases and about 5,327 words.
1Thread Pool Exhaustion on a Blocking Search Servlet
An online ticketing site runs on a Java EE 7 full-profile server. The search page is a Servlet 3.1 endpoint mapped to /search that, on every request, calls a partner inventory service over HTTPS with a 1.8-second round trip.
1,037 words, about 5 min2Lazy Loading, Query Storms, and Lost Updates in a JPA Portal
A logistics portal shows order history through a JSF 2.2 page backed by a @ViewScoped backing bean and @Stateless EJBs using JPA 2.1 (Hibernate). The backing bean calls orderService.findOrders(customerId), which returns a List<Order ; the page then iterates order.getLines() to print each SKU.
1,088 words, about 5 min3A Shared Singleton JAX-RS Resource and a Mapper That Never Runs
A telecom exposes a provisioning API built with JAX-RS 2.0 (Jersey 2) on GlassFish 4. The root resource AccountResource is annotated @Singleton because "it must not be recreated per request" and holds a shared SimpleDateFormat plus an ArrayList cache.
1,019 words, about 5 min4Poison Messages and a Serialized Singleton in a Payments Back Office
A payments back office on WildFly 8 consumes settlement messages from the JMS queue java:/jms/queue/PAYMENTS.IN with an MDB whose onMessage catches a checked BankRejectionException thrown by SettlementService.post() and rethrows it wrapped in a RuntimeException. post() is @Stateless with default transaction attributes, writes two ledger rows, and then calls a remote bank SOAP endpoint that takes up to two seconds.
1,121 words, about 6 min5Authorization Gaps Across the Web and EJB Tiers
A hospital scheduling application is packaged as an EAR with a JSF 2.2 web module and an EJB module. Roles are ADMIN, SCHEDULER, and CLERK; the app server maps LDAP groups to these role names.
1,062 words, about 5 min