Java News from Wednesday, June 22, 2005

Sleepycat Software has released Berkeley DB Java edition 2.0.42. Berkeley DB JE is an open source, non-relational embedded database written in Java. The data is exposed through "a Java Collections-style interface, as well as a programmatic interface similar to the Berkeley DB API." New features in 2.0 include:

• Support for the Java Transactions API (JTA)including XA Two Phase Commit (2PC).
• JE can now be used as a Java Connector Architecture (JCA) Resource Adapter.
• Aready to install Java Management Extension (JMX) MBean to monitor and manage database resources.
• A new Sequence API that enables concurrent generation of sequenced identifiers for use as primary keys for data values.
• Option to "relax the 'I' (isolation) in 'ACID' transactions by adding support for read committed (sometimes called degree 2) isolation. Read committed isolation ensures the stability of the current data item read by the cursor, but permits data read by this cursor to be modified or deleted prior to the commit of the transaction. This complements JE's existing ability to relax the 'D' (durability) constraints in favor of speed. These are design tradeoffs left to the developer."

Java 1.4.2 or later is required.

Tom Copeland has released PMD 3.2, an open source tool for automatically checking Java code for various classes of bugs. Version 3.2 adds three new rules:

• UseCorrectExceptionLogging
• AvoidPrintStackTrace
• CompareObjectsWithEquals

I tested this out on XOM. Surprisingly it found a lot of unread private fields, unused local variables, empty statements, and unnecessary imports that I thought Eclipse was checking for. In one case, an unused private field represented a real bug. On the other hand, the unused private methods check generated a lot of false positives.