7 notes

HeapAudit – JVM Memory Profiler for the Real World

HeapAudit is a foursquare open source project designed for understanding JVM heap allocations. It is implemented as a Java agent built on top of ASM.

Neat.

[Foursquare] [JVM] [GC]



24 notes

Callbacks, synchronous and asynchronous

In the end it works, but imag­ine what hap­pens if callback-based APIs become pop­u­lar and every jar you use with a call­back in its API has to have its own thread pool. Kind of sucks. That’s prob­a­bly why Netty punts on the issue. Too hard to make pol­icy deci­sions about this in a low-level net­work­ing library.

/cc Waffle, who said some of this before.

[JVM] [cps] [Callbacks] [Async] [Scala] [Event Loops]

“The behaviour of those objects is in part defined at object initialization time, so changing the code that is run during initialization will not affect the running application as the objects were alredy initialized. The JRebel Lift plug-in reinstantiates those singleton objects after their classes are reloaded, so changes in initialization code are picked up.”

— First-class Scala Lift support in JRebel

[Lift] [Scala] [JVM] [Reloading] [JRebel]

“Getting at such APIs, randomly and interactively, has been impossible before JSR 292, at least without statically or dynamically spinning bytecoded adapters. Now it works well in a small program. One of JSR 292’s benefits should be much easier access to Java from dynamic languages.”

— Scheme in one class

[JVM] [Scheme] [Clojure] [Dynamic] [John Rose]

“And then, to make it more pleasant to use, we write a static function that can take advantage of Java’s half-assed type inference.”

— Anatomy of an Annoyance

[Java] [JVM] [Collections] [Half-assed type inference] [Type Parameters]



1 note
“JSR 292 primarily focuses on the needs of dynamic languages. It introduces two key new concepts - a new method invocation instruction, and method handles with a corresponding type transformer factory. It also extends the grammar for Java identifiers whose spellings can be any sequence of characters (referred to as ‘Exotic Identifiers’).”

— JSR 292 and the Multi-lingual JVM (sounds hot)

[JVM] [Clojure] [JRuby] [Exotic Identifiers] [InfoQ]

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