XML and Java: XML Parsers in Java

Java XML parsers are distinguished by two pairs of traits:

• whether they are validating (checks DTD) or non-validating (checks for well-formedness, no DTD checking);
• whether they are lightweight and therefore intended for use in applets or whether they are best suited for full fledged applications.

We note that DXP and AElfred are best for applets, while XML for Java and XP are best for applications. See also the Definitions section of Part 1 of the XML and Java article.

XML Parser in Java (IBM) - validating

URL: http://www.alphaworks.ibm.com/formula/xml

According to IBM, "XML for Java is a validating XML parser written in 100% pure Java. The package (com.ibm.xml.parser) contains classes and methods for parsing, generating, manipulating, and validating XML documents. XML for Java is believed to be the most robust XML processor currently available and conforms most closely to the XML 1.0 Recommendation." IBM has released XML for Java as a parser toolkit with the rights for developers to re-distribute it within commercial products. Also known as XML4J, support for DOM Level 1 Specification [01 Oct 1998] was added with the 1.1.4 version. XML4J version 1.1.9 (and later) also supports the W3C Proposed Recommendations for Namespaces in XML and has been tested under Linux.

Java Project X Parser - validating and non-validating

URL: http://developer.javasoft.com/developer/earlyAccess/xml/

The parsers from JavaSoft included in the Early Access release of Java Project X (formerly the "XML Library") support XML 1.0, SAX 1.0, DOM Level 1, and the XML Namespaces proposed recommendation. The Release Notes state that "There are two separate parsers, sharing almost all the same code. The validating parser is slightly slower since it performs additional error checking." According to the Java Project X FAQ, "In Sun's testing using JDK 1.1.6, the validating parser (doing lots of error testing) was significantly faster than the majority of the non-validating parsers tested, and all other validating parsers. Of course, Sun's non-validating parser is faster still."

Silfide XML Parser (SXP) - validating

URL: http://www.loria.fr/projets/XSilfide/EN/sxp/

The Silfide XML Parser (SXP) is a parser and a complete XML API in Java. It is part of XSilfide, a client/server based environment. XSilfide includes SIL, the Silfide Interface Language, among other things. "The SIL DTD is organized using modules, gathering (1) the encoding of the user workspace (2) the encoding of the user informations (3) the extended query language and (4) the encoding of the queries result set."

DataChannel - Microsoft XML Parser for Java (XJ2) - validating

URL: http://www.datachannel.com/xml/developers/parser.shtml

The DataChannel - Microsoft XML Parser for Java (DCXML) will be the new XML parser included with Internet Explorer. [Netscape 5 will use expat, a C XML parser from James Clark.] "This XML Java parser was announced at the XML Developer's conference in Montreal, Canada on August 20, 1998. The XML Java technology is co-developed by Microsoft and DataChannel and allows you to take your existing server-side application and parse the data on the server. It also allows for Multiple platforms functionality." According to the press release:

REDMOND, Wash. - Aug. 20, 1998 - Microsoft Corp. and DataChannel Inc. today announced that they have collaborated to deliver XML technology, specifically, an enhanced XML parser written in the Java language. Microsoft selected DataChannel for this effort because of the company's expertise in both XML and the Java language.

The goal of the collaboration is to develop and deliver XML technology that will allow developers to write XML-enabled applications on multiple platforms, taking advantage of Microsoft XML functionality. An early beta version of the XML parser written in Java will be downloadable from http://www.datachannel.com/xml.html and http://www.microsoft.com/xml/ by the end of August.

XJ2 was formerly called "DataChannel XML Parser (DXP)". According to the December 21, 1998 press release for Beta 2, "[t]his release brings the promise of XSL and XSL pattern matching capabilities to a Java-based XML parser for the first time. This parser release includes significant enhancements from the Beta 1 version of the parser including: a validating XML engine, XSL support, and transformations of data." Major enhancements include: direct viewing of XML, additional functionality of the XML engine, XSL support, XQL Querying of XML Data, XQL transformations of data, and server-side XML, XSL, and XQL. Note: XQL is XML Query Language, a submission from Microsoft, Texcel, and webMethods to the W3C.

See also the DataChannel XML Resources page.

Larval (Tim Bray) - validating

URL: http://www.textuality.com/Lark/

Larval is Tim Bray's validating XML processor built on the same code base as Lark (below). "Larval is a full validating XML processor; it reports violations of validity constraints, but does not apply draconian error handling to them."

Lark (Tim Bray) - non-validating

URL: http://www.textuality.com/Lark/

Lark is a non-validating Java XML processor by Tim Bray, one of the authors of the W3C XML spec. It implements all of the XML 1.0 Recommendation and reports violations of well-formedness.

XP (James Clark) - non-validating

URL: http://www.jclark.com/xml/xp/index.html

XP is targeted for applications rather than applets. James Clark's XML Parser (XP) in Java comes with javadoc documentation. "XP is an XML 1.0 parser written in Java. It is fully conforming: it detects all non well-formed documents. It is currently not a validating XML processor. However it can parse all external entities: external DTD subsets, external parameter entities and external general entities." XP is a high performance parser intended for use with Java applications, rather than applets. It includes a SAX driver implementation. (Clark also has developed SP, a free, object-oriented toolkit for SGML parsing and entity management; SP can parse XML and can convert SGML to XML.)

AElfred (Microstar) - non-validating

URL: http://www.microstar.com/aelfred.html

Demo URL: http://www.microstar.com/aelfred/browser-test.html

According to Microstar, AElfred is "a small, fast, DTD-aware Java-based XML parser, especially suitable for use in Java applets. We've designed AElfred for Java programmers who want to add XML support to their applets and applications without doubling their size: AElfred consists of only two core class files, with a total size of about 26K, and requires very little memory to run. There is also a complete SAX (Simple API for XML) driver available in this distribution for interoperability."

Note that Microstar also has a commercial XML authoring tool called Near & Far Designer which has the distinction of being one of the few graphical DTD environments which is XML enabled. It is not covered in our XML Editors section because it is not written in Java.

HTML Enabled XML Parser (HEX) - non-validating

URL: http://www-uk.hpl.hp.com/people/ak/java/hex.html

HEX is the HTML Enabled XML Parser. It is "simple, 100% Java, non-validating XML parser with some hooks for more-or-less correct parsing of most HTML pages. It doesn't understand either SGML or XML DTD's but the parser API allows the application to control its operation in ways that facilitate HTML parsing. " HEX includes an implementation of SAX. HEX also implements the Java binding for the DOM core level one as per the March 1998 Working Draft.

Hubick's XML Analyzer (HXA) - non-validating

URL: http://www.hubick.com/software/HXA/

Hubick's XML Analyzer "is a pure Java tool built upon a low level XML parser (HXP) which breaks an XML file down into it's constituent productions for analysis. HXA allows one to examine the production hierarchy for any character in an XML document or document fragment. For easy reference HXA also provides links from each production in the analysis to its corresponding section in the XML specification."

XML and Java: XML Editors in Java
XML and Java: The Perfect Pair: Part 3: Editors and Parsers
XML and Java: Specialized XML Tools in Java