bytecode

Is the hotspot JVM Bytecode Interpreter a tracing JIT?

The question pretty much says it all, I've been looking around for an answer even through the VM spec but I it doesn't explicitly state it. ...

Using JRuby/Jython for Ruby/Python interoperability?

Quite-probably a silly question, as I don't know much about Java/Jython/JRuby/bytecode, but.. I stumbled across _why's unholy again today.. It allows you to output Python bytecode from Ruby code.. Basically allowing them to produce the same bytecode.. Jython outputs Java bytecode, as does JRuby.. Since these both compile to the same by...

transmit a java.lang.reflect.Proxy over a network

Is there a convenient way to transmit an object including its code (the class) over a network (not just the instance data)? Don't ask me why I want to do this. It's in an assignment. I asked several times if that is really what they meant and the didn't rephrase their answer so I guess they really want us to transmit code (not just the ...

Bytecode and Objects

Hey everyone, I am working on a bytecode instrumentation project. Currently when handling objects, the verifier throws an error most of the time. So I would like to get things clear concerning rules with objects (I read the JVMS but couldn't find the answer I was looking for): I am instrumenting the NEW instruction: original bytecode ...

Editing a .class file directly, playing around with opcodes

Hi, today I just tried to play a little bit around with the opcodes in compiled java class file. After inserting iinc 1,1 the java virtual machine responds with: Exception in thread "main" java.lang.ClassFormatError: Truncated class file at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.de...

How do you access byte level information in JavaScript?

The generally accepted answer is that you can't. However there is mounting evidence that this is not true based on the existence of projects that read in types of data that are not basic HTML types. Some projects that do this are the JavaScript version of ProtoBuf and Smokescreen. Smokescreen is a flash interpreter written in JS so if i...

Detect use of older Java libraries

Is there a third party library to detect the use of a Java 1.5 library when compiling with a 1.5 compiler with -source 1.4 and -target 1.4? I could use a 1.4 rt.jar in the bootclasspath however I hope there is a better way. To be used, for example, to fail the compile/build if a newer library is used. ...

Is there a .NET class to handle encryption?

I need to encrypt bytecode to send over a connection to a webservice, preferably using a GUID as a key. I have done a bit of research and found several classes developed for a similar purpose, but haven't been able to turn up much that is built into the Windows libraries. My question is: Is there something built in to C# that performs t...

Java bytecode compiler benchmarks

Q.1. What free compiler produces the most optimal Java bytecode? Q.2. What free virtual machine executes Java bytecode the fastest (on 64-bit multi-core CPUs)? Q.3. What other (currently active) compiler projects are missing from this list: http://www.ibm.com/developerworks/java/jdk/ http://gcc.gnu.org/java/ http://openjdk.java.net/g...

Eclipse + Django: How to get bytecode output when python source files change?

Whenever I change my python source files in my Django project, the .pyc files become out of date. Of course that's because I need to recompile them in order to test them through my local Apache web server. I would like to get around this manual process by employing some automatic means of compiling them on save, or on build through Ecl...

Check if Java bytecode contains debug symbols

Hello, I would like to know how can I check if a compiled Java class contains debug symbols. The problem is that I compile an application from ant with debug="on", but a specific JVM throws an exception: it says that the debug symbols are missing. Thanks. ...

Programming in Java bytecode

I'm looking to write a short program (maybe a Hello World) in Java bytecode. I just want to write the bytecode using my text editor and run it. How would I do this? Got an example? Thanks! ...

Load Java-Byte-Code at Runtime

I got some java-byte-code (so compiled java-source) which is generated in my program. Now I want to load this byte-code into the currently running Java-VM and run a specific function. I'm not sure how to accomplish this, I digged a little bit into the Java Classloaders but found no straight way. I found a solution which takes a class-fi...

Is it more efficient to access array elements through the array than to get them through a function?

I'm thinking about making an object that consists of a large grid, stored in a two dimensional array, and functions that work on that grid. If I want to iterate through the elements in this array outside of the object, the most readable and privacy-respectful way to access each grid element would be to use a function like grid.getElemen...

Generating methods with generic types with Asm bytecode generator (ClassWriter)

Defining simple getters and setters is easy using Asm (and fortunately it is even explained in their FAQ). But one thing that is not mentioned, and for which I have been unable to find documentation, is how to implement these using generic type information. I am actually able to determine generic type information itself quite easily (si...

Clarifications on Bytecode and objects

Hello everyone, I am writing a Bytecode instrumenter. Right now, I am trying to find out how to do that in the presence of objects. I would like some clarifications on two lines I read in the JVMS (section 4.9.4): 1) "The verifier rejects code that uses the new object before it has been initialized." My question is, what does "u...

Is there a java classfile / bytecode editor to edit instructions?

Is there a utility (or eclipse plugin) for editing java class files? I'd like to manipulate the bytecode of a java class file without recompiling it nor having a complete buildpath. E.g. to rename methods, add/delete instructions, change constants etc. The only utilities I found are: classeditor but it's very limited in functionalit...

Is it possible to view bytecode of Class file?

In Java,source code is compiled into bytecode which is actually Class file. Is it possible that we can view bytecode of Class file? If it possible, Can we edit it? Is there any eclipse plugin available? -Abhishek Jain ...

How make Eclipse instrument classes at build time?

Sometimes I have to perform some custom bytecode transformation. I have used mainly asm and javaassit. Inside eclipse usually I run my code with the -javaagent jvm parameter. Outside eclipse I use maven, ant, or the command prompt to invoke the weavers before running the application code. But the point is that: I would like to perform...

How to strip source from distutils binary distributions?

I want to create a bytecode-only distribution from distutils (no really, I do; I know what I'm doing). Using setuptools and the bdist_egg command, you can simply provide the --exclude-source parameter. Unfortunately the standard commands don't have such an option. Is there an easy way to strip the source files just before the tar.gz, z...