What is the default maximum heap size for Sun's JVM from J2SE 6 (i.e. equivalent to setting -Xmx)? Looks like for J2SE 5 with a server-class machine, it's Smaller of 1/4th of the physical memory or 1GB. Bonus question: Looks like for IBM's JVM you can ask it java -verbose:sizes -version Can you similarly ask Sun's JVM? Edit: ...
Is there any DOS based JVM available? ...
Hi, I came to know that JRE /JVM was not built using Java. The Sun JRE was built in C and IBM JRE was built in SmallTalk (First Object Oriented Language). Pleas help me with answer. Thanks in advance. ...
Is there an easy and secure way to do this? I know I can download and kinda hack all that stuff, but I'm developing a comercial application and one of the customers can't open menus inside the app and I have no idea why. It runs fine in all my test phones, so I imagine that theres something with his JVM version, but I dont want to risk s...
I'd like to have a small (not doing too damn much) daemon running on a little server, watching a directory for new files being added to it (and any directories in the main one), and calling another Clojure program to deal with that new file. Ideally, each file would be added to a queue (a list represented by a ref in Clojure?) and the ...
If not, why not always include sources file into "open source" JAR distributions ? (thanks in advance if you have some official weblinks that explain your answers) ...
I'm working on a Sudoku solver at school and we're having a little performance contest. Right now, my algorithm is pretty fast on the first run (about 2.5ms), but even faster when I solve the same puzzle 10 000 times (about 0.5ms for each run). Those timing, of course, depend of the puzzle being solved. I know the JVM do some optimizatio...
In which language garbage collection algorithm is implemented for java.i think c, please confirm? ...
I am doing some reviison from the lecture slides and it says a constructor is executed in the following way; If the constructor starts with this, recursively execute the indicated constructor, then go to step 4. Invoke the explicitly or implicitly indicated superclass constructor (unless this class is java.lang.Object) Initialise the f...
Hi. Could anyone advice a book (or any other source) that would thoroughly reveal internals of JVM memory management & garbage collection (optimization, work, circular references, pecularities, discussions for various JVM impls...)? [What I've found so far are separate articles devoted to various aspects but no weighty tome :). Some goo...
From Sun JRE performance tuning whitepaper, -XX:+AggressiveOpts flag is described as: Turns on point performance optimizations that are expected to be on by default in upcoming releases. The changes grouped by this flag are minor changes to JVM runtime compiled code and not distinct performance features (such as BiasedLoc...
I'm developing a new language. My initial target was to compile to native x86 for the Windows platform, but now I am in doubt. I've seen some new languages target the JVM (most notable Scala and Clojure). Ofcourse it's not possible to port every language easily to the JVM; to do so may lead to small changes to the language and it's desi...
I am testing the performance of a data streaming system that supports continuous queries. This is how it works: - There is a polling service which sends data to my system. - As data passes into the system, each query evaluates based on a window of the stream at the current time. - The window slides as data passes in. My problem is t...
I am interested in writing a Java program which does the following. Attach to a currently running Swing window or applet, running in another JVM Alternatively, load a Java application so as to be able to do the above Read colors from the window Send mouse and keyboard events to the window I am hoping to make some sort of testing an...
I've read in many threads that it is impossible to turn off garbage collection on Sun's JVM. However, for the purpose of our research project we need this feature. Can anybody recommend a JVM implementation which does not have garbage collection or which allows turning it off? Thank you. ...
Hi, I'm working with JNI and trying to unload (destroy) the VM using DestoryJavaVM function (I first call DetachCurrentThread method). It seems like the it has now influence on the VM and it is still up after the call. I read in old Sun posts that DestoryJavaVM had problems in the past (JDK1.1-1.3 in 2001) but I'm using JRE 6 and it pro...
I have came from another question to this one: How can one start with Java (JVM) ecosystem? What are beginner, intermediate and advanced knowledge-bases (bags!)? To be honest Java ecosystem was always a bit confusing to me, so it would be very helpful to provide some "reference references" and "defacto tutorials" for learning (curve!) J...
I tried to increase the heap size like the below C:\Data\Guru\Code\Got\adminservice\adminservice>java -Xms512m -Xmx512m Usage: java [-options] class [args...] (to execute a class) or java [-options] -jar jarfile [args...] (to execute a jar file) where options include: -client to select the "clie...
Can I use other JVM languages besides Java (e.g. jruby, jython, clojure) to program for android, or is it java only? There was a similar question asked over a year ago but I wasn't sure if there'd been any change since then. ...
I'm preparing the SCJP exam with the almost official study book ("SCJP Sun Certified Programmer for Java 6 Exam 310-065") I understand that Java programming is writting code that fulfills a certain high-level contract; So that Java can stay platform-independent. However, I have trouble understanding and remembering things when it comes...