Marion's blog

Introducing JSONB

JSONB, a structured format for storing JSON has been introduced in a message by Andrew Dunstan posted on PostgreSQL’s website. Andrew Dunstan authored JSONB together with Oleg Bartunov, Teodor Sigaev, and Peter Geoghegan; and reviewed by Andres Freund. Andrew described that this new format accepts the same data as the JSON type yet it is stored in a format that does not need reparsing the original text in order to process it. This process makes it more ideal for indexing and other operations wherein irrelevant whitespace is removed and order of object keys is not kept. Also, duplicate objects keys are not kept – the only one stored is the later value for a given key.

He also mentioned that this features was created out of the previous work by Oleg Bartunov and Teodor Sigaev which aimed to offer similar facilities to a nested HStore type, however, it was later on verified to have some major compatibility issues.

Meanwhile, Peter Geoghegan wrote in his blog that jsonb_hash_ops alternate GIN operator class by Alexander Korotkov, one of the contributor of JSONB not credited in the JSONB commit message, deserves an honorable mention. “By combining GIN with hashing of either key/value pairs, or array elements, resulting indexes can give great performance for sophisticated “containment” type queries against JSON documents. Indexes are a fraction of the size of the data indexed, index scans are incredibly fast, and yet these GIN indexes make indexable very complex nested “containment” queries. The results are so impressive that at last November's pgConf.EU conference, an EXPLAIN ANALYZE comparative example in a presentation given by Oleg and Teodor was greeted with sustained applause.” Peter mentioned.

JSONB has made in the upcoming 9.4 release of PostgreSQL, an open source Object-Relational Database Management System (ORDBMS) known for its reliability, data integrity and correctness.

JCACHE Has Arrived

The most awaited JCACHE also known as JSR 107 – Java Temporary Caching API has finally been released in March 18, 2014. This specification request has been started way back in 2001, nevertheless, over 80% voted for its inclusion in the platform on a 2012 Java EE 7 survey.

In the original proposal posted in the Java Community Process' website, JCACHE has been described as a specification that standardize process caching of Java objects in a way that allows an efficient implementation, and removes from the programmer the burden of implementing cache expiration, mutual exclusion, spooling, and cache consistency. Objects whose type is not known until runtime can be cached, but only those which implement the serializable interface can be spooled.

The main purpose of JCACHE is to let developers solve usual problems by only writing little code as possible. This will work on any Java platform and will be beneficial to server platforms like servlet container.

It is also said that there are no specifications yet that handle automatic creation and refresh of temporary, in-process data shared across threads. The following are mentioned issues with existing specifications that can be addressed through JCACHE:

    Java Naming Directory Interface (JNDI) is used for searching objects by name and an interface for caching implementation. But this application requires checking expiration of retrieved objects after each look up, and synchronizing creation and binding of a new object. Per object cache attributes (e.g., expiration time) would require introduction of an additional level of indirection: the application would look up a cache handle and use one of its methods to access the associated object.

Java 8: Final Release

Oracle has finally announced the General Availability of the most anticipated open-source implementation of Java SE 8 (Java Standard Edition 8) which is the JDK 8 (Java Development Kit 8) last March 18, 2014. JDK 8 was supposed to be released last September 2013 but was delayed to work on its security issues and other bugs.

The following are some of the features and improvements of JDK 8 mentioned in an article published at Oracle’s website:

Java Programming Language: Introduction of a new language feature calledLambda Expressions which let you express instances of single-method interfaces more compactly.

Collections: Performance Improvement for HashMaps with Key Collisions.

Compact Profiles contain predefined subsets of the Java SE platform and enable applications that do not require the entire Platform to be deployed and run on a small devices.

Security enhancements such as: Client-side TLS 1.2 enabled by default; stronger algorithms for password-based encryption; SSL/TLS Server Name Indication (SNI) Extension support in JSSE Server; SHA-224 Message Digests; 64-bit PKCS11 for Windows; New rcache Types in Kerberos 5 Replay Caching; and more.
JavaFX: The new SwingNode class enables developers to embed Swing content into JavaFX.

New Tools: jjs command is provided to invoke the Nashorn engine;java command launches JavaFX applications; java man page has been reworked; jdeps command-line tool is provided for analysing class files; Java Management Extensions (JMX) provide remote access to diagnostic commands; jarsigner tool has an option for requesting a signed time stamp from a Time Stamping Authority (TSA); and improved Javac tool.

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