Capturing Network Communication Between Two Processes On the Same Machine…
Have you ever run snoop on Solaris or tcpdump on Linux or AIX and discovered that these tools cannot capture IP-based communication that occurs between two processes on the same machine? Or, Wireshark (formerly, Ethereal) on Windows? Only to discover the same limitation?
Capturing JVM TCP Traffic
Any time you have a distributed application, there is network communication involved. Capturing this network traffic can be instrumental in diagnosing and solving problems. Generally, to capturing network traffic, superuser privledges, timing, and a bit of luck is needed. Often, the appropriate…
Websphere v6.x Classloaders
Building on the ideas introduced in the last article, a J2EE Application servers classloaders are explored in this installment. In particular, Websphere Application Server v.6.x Classloaders are introduced. The J2EE Spec provides some guidance regarding J2EE Application Servers, but as with so many…
JEE 6 Draft Proposal Is Available For Public Review
Check out JSR 316 and this article. There is also a Slashdot.org thread on the subject.
Java Virtual Machine Classloaders
Classloaders are responsible for finding and loading classes that are requested in Java code executed inside a Java Virtual Machine. Classloader-related issues are among the most difficult to troubleshoot in the Java/J2EE technology stack.
JVM process Virtual Memory Usage (Resident Set Size) On A Linux 2.6.25 Kernel
This article expands on the previous Virtual Memory post by exploring Resident Set Size growth while running a Java program that will consume all available Java Heap memory. Four different JVM implementations are used to compare results of these experiments. These JVMs come from two different…
Dumping the contents of a JAAS Subject
In the last article, JAAS was introduced. An authenticated calling-entity (perhaps a user), has a JAAS Subject. This JAAS Subject contains some combination of Principals, Public Credentials, and Private Credentials. It can be very helpful to dump the contents of this JAAS Subject for debugging…
JAAS Authentication — An Introduction
This article introduces JAAS authentication via a relatively simple example. The example presented here is based upon the Sun tutorial of the same subject. The thinkmiddleware.com example extends the tutorial to use LDAP to authenticate users.
An Openldap Directory Server
The recent JNDI article and an upcoming JAAS article require an LDAP server. This tutorial will walk through the basic details of reproducing the Openldap Server used in these two articles.
JNDI — Java Naming & Directory Interface
While researching an upcoming JAAS article, the decision was made to use JNDI to interact with the Openldap server that was stored user information. JNDI is used extensively in the J2EE landscape; so, exploring JNDI separately from JAAS seemed in order.
Ant — Build Control
I’ve mentioned that for larger projects/examples on thinkmiddleware.com, Ant would be used. The Java Security Manager article was the first time it was used. Although, the full details of the source code were not included, Ant was used.
The Java Security Manager
In the last post, the Java Standard Edition and Java Enterprise Edition security features were introduced. This is the second in a series of articles that introduces each Java security feature in depth. This article introduces the Java Security Manager and the sandbox it creates for a Java…