A while back I came across findbugs, which is a static analysis tool that can be used to locate bugs in Java programs. Findbugs is able to identify a number of bug patterns, which range from bad practices to performance and multithreaded programming bugs. Findbugs can be invoked through a graphical utility, or by running [...]
I have been reading through the Java virtual machine specification, which covers all the details needed to implement a JVM. Once thing the specification talks about in detail is Java bytecode, which is the machine independent code that is executed by the virtual machine implementation. At various places in the specification I wondered what the [...]
The Sun JDK has included an SNMP agent since version 5, and the agent has a number of objects in its MIB that provide runtime utilization data. The current set of objects include thread utilization counters, garbage collection events, time spent performing garbage collection, heap usage, class loader activity, compiler metrics, etc. Graphing these values [...]
In my previous post, I discussed how jmap can be used to view the contents of the Java heap. Jmap is a wonderful utility for viewing heap utilization at a specific point in time, but it’s not the best utiltiy for answer questions like “which call stack is allocating objects of type foo?”, or “how [...]
Java has become one of the most successful languages to hit the IT industry. One of the reasons behind it’s high rate of adoption is that fact that Java manages memory resources for the programmer. This makes programming significantly easier, but introduces additional complexity, since engineers need to size the Java heap and pick a [...]
I wrote yesterday about the jmap utility, which is a great utility for better understanding the arrangement of the JVM’s heap. Each thread that lives inside the JVM also contains an execution stack, which is used to store local variables and state information to allow function calls to work. The Java SDK /JRE comes with [...]
