http://docs.oracle.com/javase/specs/
Understanding JVM Performance - It is Fast - Very Fast! JVM code can be just as fast as the equivalent native code. This might come as a shock to some people. Yes - JVM code (like Java or COBOL) can the same speed as native code (like C++ or COBOL). This is generally true. However, in this case I am looking at batch processing, a type of programming which is very common in commercial settings. C#-VSLP vs J-VSPL, Interesting Stuff Shown Up VSPL - So simple an amoeba can understand it! A Report Of VSPL From C# To Java Gives Some Surprising Results I need a cross platform, easy to use, multi-threaded test system. VSLP has involved into a powerful testing tool, so I just wanted the lastes version in Java rather than C#.
JDK: DirectByteBuffers Seem V.Slow On Sun JDK Recently I have been working on the next (GA) release of JVM COBOL from Micro Focus. Hidden away in the guts of part of this system is some JNI. It was using DirectByteBuffers, which are supposed to be the best way to pass blocks of memory from managed to native code. But they are slow! The end of the story is that I found a better way of implementing the functionality which did not require DirectByteBuffers. I am also sure there are situations where they are great.
Tuning The JVM For Unusual Uses - Have Some Tricks Under Your Hat Knowing a little more about the guts of the JVM can make a huge difference, especially if you are coding off the beaten track.Speed counts!I have been working with Java all the way from Java 1.0 whilst I was as post doc' at Zurich University. Back then I used Java to create simple molecular visualisation applet for web-browsers.
Java On Ubuntu 64 Massively Faster Than Vista 32 Out of curiosity I ran my standard VSPL speed testing in with (the Java implementation) on the same machine in both Ubuntu and Vista (dual boot). Ubuntu was either near the same speed or much faster on each test. To be honest, I was not out to compare the two operating systems; I booted into Ubuntu so I could do some comparisons of other scripting languages to VSPL. Java Type 'Erasure': What A Pile Of Bollocks One thing which really gets up my nose is giving a complicated sounding name to something simple. Type Erasure is one of the worst examples in IT. Why - because the types ARE NOT ERASED.
For the record - my life with Java :) To Whom It May Concern, 26 April 2011 I have watch Java grow as a language and the JVM mature as a technology over the last 15 years. From the early days of rendering molecular structures in a web browser during my time as a post doctoral researcher at the University Of Zurich, the simplicity of the object structure, automatic memory management and machine virtualization of Java have continuously proven invaluable in many of my software projects.
download.oracle.com/javase/6/docs/technotes/guides/jni/spec/functions.html#nio_support JNI Functions Chapter 4 This chapter serves as the reference section for the JNI functions. It provides a complete listing of all the JNI functions. Escape Analysis, Values Types And JVM Optimisation I was going to post the code for my high speed JVM based transaction demo. But it has been a funny kind of day and so that will have to wait. Here is a post about an amazing optimization that the Hotspot compiler can do for JVM code. Java runs on the JVM and the JVM (Java Virtual Machine) does not have a concept of complex types other than objects. Invokedynamic in JRuby: Constant Lookup This is the first of a set (not a series...there's no particular order) of articles I'll write on how JRuby is using invokedynamic. Hopefully they will show Rubyists how drastically invokedynamic is going to improve JRuby, and show other JVM language folks how to use invokedynamic effectively. Hello friends! I figured it's about time for me to start writing a bit on how JRuby is actually using invokedynamic.
Tackling Legacy Languages With JVM Invokedynamic Invokedynamic can be considered for dynamic languages like Magik or Ruby. But - there are very good reasons for moving legacy code like C or COBOL onto managed evironments; invokedyamic might just be the key to making these run super fast (potentially faster than native). This post is not a worked example and it is only a start. However, I suspect there is something here which can be very successful at making more legacy code constructs run at native speeds on the JVM. The issue being solved if the type free memory model of legacy languages.
Java Is Not Going Anywhere Soon! Despite rumours to about the imminent demise of Java, it will be with us and growing as a technology for quite some time to come: Here are my five reasons Java is not going anywhere soon (in HD if you watch on Youtube). Also, at the bottom of this post are some interesting job stats which help drive the point home. So - from these graphs it would appear that if you want to be paid for writing code - rather than do it for love - go for Java. I love for love, I work for money!