57 articles tagged Java.
In the second part of this series we continue to explore how Unix-like operating systems implement the networking API and threading API. In particular, we are supremely interested in how the kernel allows server programs accept incoming connections. Part two explores implementing concurrency in…
Read article: Concurrency And Server-Side Networking APIs — Part 2This article explores how a Sun Hotspot JVM behaves when accepting incoming TCP/IP socket connections. The behavior of native server programs–written in C–are also explored to better understand how concurrency can be achieved. Then, a comparison of how these runtime environments implement…
Read article: Concurrency And Server-Side Networking APIs — Part 1Several terms have been used liberally throughout articles on thinkmiddleware.com. A moment should be taken to formally define them. I am going to attempt to present these concepts in as generic a sense as possible, but the truth of the matter is, every OS has its own threading model and…
Read article: Threads, Threads Everywhere. And, Not a Needle In SightIt happens. End users are complaining about a slow system or a request that never returned. You log into a production middleware server and notice that a java process is consuming an entire CPU or worst every available CPU on the box. It has happened again–a thread(s) has gone into an infinite loop…
Read article: Mapping An LWP Using Excessive CPU Time To a Java ThreadAs I’ve pointed out in several previous articles, I like the jdb command line debugger that is available with the Sun JDK. This debugger can actually be used with any spec-compliant JVM. The JPDA specification defines the interfaces and services that are used by remote debuggers and profiles. The…
Read article: Configure Your JVM For Use With a Remote DebuggerThread dumps are the basic diagnostic tool for JVMs. Thread dumps present a partial state of each Java thread in a running JVM. I say partial because it doesn’t present all information that captures the state of a Java thread. The state of a running Java thread is stored in a series of data…
Read article: Generating Thread DumpsThis article isn't a comprehensive JVM Java heap sizing and garbage collection tuning document; its goal is simply to outline options for identifying which type of Object(s) are consuming the majority of memory in a running JVM--troubleshooting memory leaks in the Java heap. As usual, I focus on…
Read article: My JVM ran out of memory! What objects are consuming all of the memory?In this article, I wanted to present a brief tutorial regarding troubleshooting deadlock conditions in JVMs. Before one can troubleshoot a deadlock condition, one needs to understand what it is; to this end, I have written a simple Java program called DeadLock.java, which is guaranteed to very…
Read article: Troubleshooting Deadlock Conditions With Monitor Locks In Java Virtual MachinesI recently had a conversation with a colleague that reminded me of a another discussion with my Masters Project advisor a couple of years ago when I was exploring research topics. The topic under discussion was Reverse Engineering --in particular, Software Reverse Engineering. It sounds really…
Read article: The Definition of Reverse Engineering, JVMs, and the Java programming languageNote: this is another article that I wrote a while ago using a Java Disassembler that no longer seems to be available--d-Java. There are numerous Java Disassemblers on the Internet. Two more that could be used are mentioned in the reference section: Jasper & Kimera. They can produce the Jasmin…
Read article: The Java Instruction Set, Assemblers, and Disassemblers
