JavaCore.

Advanced Exception handling for the Java Virtual Machine.

News:

• Mon Jan 15 09:11:28 2001 (burton): JavaCore 0.8.0 Released. As usual downloads can be found here.

Overview:

JavaCore is an enhanced debug facility for the Java platform. It enables "core" dumping when an un-handled Exception is thrown. This has been a facility UNIX developers have enjoyed for years and (to some extent) it is now available to Java developers. There is a difference in use which may be confusing to some people. JavaCore does not terminate the JVM. It writes system information (stack trace, class loader information, CLASSPATH, system properties, memory info, etc) to an XML file which can then be loaded into other applications for further analysis.

JavaCore provides an implementation of java.lang.Exception and an additional library package (net.sourceforge.javacore) which modify your JVM so that you can control when core files are written.

Everything here has the engineering principle of stablity first. JavaCore installs at such a low level that it is important to use redundancy and defensive programming. A goot example is that Exceptions thrown/caught from within JavaCore are kept to a minimum and where Exceptions could be thrown (Integer parsing, null strings, etc) checks are done. Also, JavaCore won't process Exceptions which originate from within itself (even if you tell it to).

Features:

• Store Java Runtime and Exception information in core XML file
• Dynamic and inclusionary dumping of java Exceptions
• Configuration via javacore.properties file
• User, JVM, and System javacore.properties
• stderr, stdout, and file logging
• instanceof detection of Exceptions
• class name detection of Exceptions
• package name detection of Exceptions
• TODO: JPDA support
• TODO: JODE (decompiler) support

Install:

Please note that before you install JavaCore you should backup your Java Virtual Machine so that you can reverse the changes it makes if you have a problem. JavaCore will also slow down your JVM in high use environments. For development purposes this performance hit is irrelevant.

There are two ways to install JavaCore:

• Install under java.lang.Exception. You need to install all classes provided with JavaCore into your current JVM (this needs to be done to all JVMs installed on your system).
  • Under JDK 1.1.8:

    
            cd JAVA_CORE/classes
            jar uf JAVA_HOME/lib/classes.zip java/ net/
            

  • Under JDK 1.2.x and 1.3:

    
            cd JAVA_CORE/classes
            jar uf JAVA_HOME/jre/lib/rt.jar java/ net/
            

• Install within your application. Some developers and situations may require that JavaCore not overwrite the default java.lang.Exception. The source from the JavaCore java.lang.Exception should be incorporated into your own Exception object (you need to pay attention to licensing issues here) and JavaCore will still function. Only applications that throw your new Exception will use JavaCore.

After installing the classes you need to provide a javacore.properties file which can be used. This file should be located in either HOME/javacore.properties, JAVA_HOME/javacore.properties, or /etc/javacore.properties. You could use the default version which ships with JavaCore as a template. This is located in JAVA_CORE/src/properties/javacore.properties. You should read through this file as additional instructions for configuration are provided.