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“Micro-footprint” DB goes J2ME

Oct 6, 2006 — by LinuxDevices Staff — from the LinuxDevices Archive — 2 views

[Updated Oct. 11] — McObject is shipping a “micro-footprint” version of its dual-licensed Java object database. The company says Perst Lite works with Sun's J2ME (Java 2, micro edition), yet retains “most of the features” of Perst, including a variety of index options, collections methods, and ACID transactions.

McObject says Perst Lite's footprint is 30 percent smaller than Perst Standard Edition, which in turn has a footprint ranging from 30KB to 300KB. McObject Spokesperson Ted Kenney explains, “It varies so much because Java loads classes on demand. So an application that uses the bare minimum of Perst or Perst Lite will have a smaller code size.”

To make Perst Lite work with J2ME, a utility was created that generates serialization and de-serialization code for each Java object. This circumvents J2ME's lack of “reflection” capabilities — a shortcoming that had previously limited the availability of OODBMSs (object-oriented database management systems) for J2ME, the vendor says.

Another touted Perst Lite feature is re-written object cache logic, which avoids “weak references” — another missing capability in J2ME, McObject says.

Additional touted Perst Lite features include:

  • B-tree, Patricia Trie, Bit index, T-Tree, and R-Tree indexes
  • List, Relation, and Set collections
  • Transactions supporting the ACID properties (atomicity, consistency, isolation and durability)
  • Multithreaded access
  • Data encryption
  • Asynchronous replication


Both Perst and Perst Lite are available under a commercial licenses, or under the GPL for use in open-source applications. Perst launched in 2003. Perst Lite supports Connected Device Configuration (CDC) and CLDC-1.1, both of which are J2ME “configurations.” It also supports Blackberry JDE. Further details are on McObject's website.

Object databases store objects in their native format, and thus do not require translation into SQL or another relational database language. Another open source object database that supports .Net as well as Java objects is Db4o, from DB4Objects, which recently added Wind River founder Jerry Fiddler to its board of directors.

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