Free java bytecode compiler software for linux

JProfiler is an award-winning all-in-one Java profiler. JProfilers intuitive GUI helps you find performance bottlenecks, pin down memory leaks and resolve threading issues.
Even though JProfiler has a powerful feature set, its a Java profiler that is extremely easy to use! JProfilers user interface provides a unified view on the profiled application and puts all the information you need right at your fingertips with its intuitive hierarchy of views.
Configure your application for profiling
When starting up JProfiler, the start center is brought up. Here you can manage and start your profiling sessions. To configure your application for profiling, change to the "New session" tab and click on the New session button. Enter the required information into the session config dialog as described below and select Ok to start profiling. Thats all it takes. Note the Help button which appears on all of JProfilers dialogs displays a context sensitive explanation of all features.
While the configuration dialog displays numerous options that you will not want to miss after becoming familiar with JProfiler, entering the basic pieces of information is really very simple:
1. Enter a name for your session.
2. Enter the name of your main class.
3. Enter your class path.
4. Press Ok.
Before profiling is actually started, the profiling settings dialog is displayed where you can select the focus for your profiling run. Although profiling produces an overhead when running your application, you can minimize it by choosing a setting for which JProfiler only records information that is interesting for you.
If you want to fine-tune your profiling settings, the [Edit] button brings up a dialog with all available configuration options for profiling.
Observe classes and allocations
To find out what is going on the heap in terms of objects and classes, turn to the classes monitor. It gives you continuous updates and lets you set marks to observe changes over time. To see references, allocations and object data for your selection, you can take a snapshot by clicking on the camera in JProfilers toolbar.
If you want to know where your objects are allocated, you can go to the allocation monitor. Here, you can inspect the call tree and find out what method calls have caused the allocation of a selected class or package. Just like in the allocation monitor, you can display this data for live and garbage collected objects.
An cumulated overview on which methods are responsible for allocations is given by the allocation hot spots view. Each hot spot can be expanded and the backtraces that lead to the invocation of the hot spot are displayed. You can also mark the current values and view the differences in allocations over time.
Find memory leaks
JProfilers heap walker works like a browser: it displays a current set of objects that can be changed by adding selection steps with the [Use selected] button. You can inspect the current object set in the four views of the heap walker.
In the classes view, you can select one or several classes and add a selection step. The new object set will contain only the selected instances. This is often the first thing you want to do after taking a snapshot. You can perform this step automatically by invoking the heap walker from the classes monitor.
The allocations view of the heap walker shows the allocation tree and the allocation hot spot list of the current object set. You can add a selection step for one or multiple allocation spots or hot spots. The new object set will then be restricted to the selected instances only.
When youre looking for the cause of a memory leak, the reference view is the most important view in JProfiler. Here, you can find out why an object has not been garbage collected. Use the "Show path to GC root" function to show where the JVM hangs on to the selected instance.
Not only is the heap walker your first stop for finding memory leaks, it also makes for an excellent debugging facility. In the data view, you can inspect instances, arrays and classes in the current object set and navigate along references. There are many situations where the usual debugging approach will fail and JProfiler will help you find out.
Zoom in on performance bottlenecks
Controlling your applications performance may be driven by quality of service constraints or by general quality assurance, JProfilers CPU views lend themselves naturally to both approaches.
To record CPU data, you switch to the CPU section and click on the recording button in JProfilers tool bar. The first view in the CPU section shows the invocation tree, cumulated for all threads. To find performance related problem spots, just follow the big percentages when opening the tree nodes. Also, the absolute times and the number of invocations that are displayed for each node can help you in getting a feeling for the situation. Once you become familiar with JProfiler, you may want to customize this view to best fit your personal preferences.
The invocation tree is a top-down view on the method calls of your application. This viewpoint is most useful when you experience an actual performance bottleneck in your application. If you want to improve overall performance, a bottom-up view may be more applicable.
This kind of view - called hot spots view - shows the methods where most of the time is spent. By opening these nodes you get backtraces which show the various invocation paths together with the percentages of their contributions. Note that by default, method calls within Java core classes are not shown separately - each of your library calls is treated as opaque. You can change this behavior by deactivating the corresponding filter sets.
The method graph combines both viewpoints. Incoming and outgoing method calls are presented in the same way. For a number of situations, the method graph can give you more insight than the invocation tree and the hot spots view. The best strategy is to use the invocation and hot spots views first and switch to the method graph for detailed analysis.
Solve thread-related problems
Threads can be exceptionally difficult to debug, especially if you dont have sufficient information on the actual sequence and status of the threads in your application. JProfilers thread views provide you with exactly this knowledge.
The thread history view shows a continuous update of the lifelines of all threads on the horizontal axis. The names of the threads are displayed on the vertical axis in the order of their creation. Each color signifies a different thread status. Orange means that the thread was sleeping, green stands for a runnable thread while red is displayed if the thread was waiting for a monitor. You can zoom in and out to your desired detail level or have the time axis fit your windows size automatically.
If youre more interested in whats happening right now, the thread monitor view is the right place to look at. Here, you can sort threads, filter with respect to thread status and view additional information on each thread.
Should you ever have a deadlock in your application, the deadlock detection graph will help you analyze the involved threads and the locking situation. Simple deadlocks like the one shown could be worked out by hand from the other views, but for complicated deadlock involving a greater number of threads this view is indispensable.
Reducing general monitor contention and debugging locking sequences requires a detailed view of the current monitor usage and a history of all monitor-related events. JProfiler has both. Below you see the monitor usage history which shows a blocking event together with the stack trace of the waiting thread.
Keep an eye on your JVM
Monitoring cumulative parameters of the virtual machine can be a highly fruitful activity, even if everything seems to be all right. Measuring and observing parameters like heap size, object count, loaded classes and thread numbers can point to dangerous trends and problematic behavior to look out for. In its VM telemetry view section, JProfiler features various telemetry controls which provide you with the information you need to stay one step ahead.
The number of objects on the heap, split in arrays and non-arrays. This is your first stop if you are suspecting a memory leak. All objects with live references are included, as well as those which are unreferenced but the garbage collector hasnt had a chance to collect yet.
The garbage collector activity which displays freed and moved objects. If your application is thrashing the heap excessively, this will show up here. Moving large numbers of objects places a high burden on the virtual machine and can lead to temporary freezes. Mostly this occurs when the virtual machine is enlarging the heap.
The number of threads in the virtual machine, split in active and inactive threads. This is useful if you create a large number of threads and need information on changes in their total number and how many of them actually run.
Enhancements:
- New futures:
- rewritten eclipse 3.x integration
- rewritten IDEA 4.x integration
- IDE integration for JDeveloper
- IDE integration for Netbeans 4.0
- considerably reduced memory consumption
- improved long-term stability for profiling
- heap walker: in the cumulated incoming reference view, reference holders as well as referenced objects can be displayed and selected
- option to keep the profiled JVM alive
- support for Java Web Start 1.5
- CSV export for graphs
- enhancements in XML export for trees
- integration wizard for profiling servers in IBM WSAD
- integration wizards for Pramati 3.5 and Pramati 4.x application server
- integration wizard for Websphere 4.0 Advanced Edition
- integration wizard for Sun Java System Web Server
- integration wizard for Sun Java System Application Server
- integration wizard for Oracle 10g Application server
- integration wizard for Apple WebObjects Developer 5.x
- snapshot files (*.jps) can be opened from the command line and from the Windows explorer
- JBuilder IDE integration now supports JBuilder 2005
- much better appearance of the JProfiler GUI with Windows native look and feel
- JProfiler GUI now also runs under Java 1.5
- Bug fixes:
- monitor statistics were broken
- invalid class files caused a shutdown of the profiled application
- many bug fixes in the GUI

Obfuscated Tiny C Compiler (OTCC) is a very small C compiler I wrote in order to win the International Obfuscated C Code Contest (IOCCC) in 2002.

My goal was to write the smallest C compiler which is able to compile itself. I choose a subset of C which was general enough to write a small C compiler. Then I extended the C subset until I reached the maximum size authorized by the contest: 2048 bytes of C source excluding the ;, {, } and space characters.

I choose to generate i386 code. The original OTCC code could only run on i386 Linux because it relied on endianness and unaligned access. It generated the program in memory and launched it directly. External symbols were resolved with dlsym().

In order to have a portable version of OTCC, I made a variant called OTCCELF. It is only a little larger than OTCC, but it generates directly a dynamically linked i386 ELF executable from a C source without relying on any binutils tools! OTCCELF was tested succesfully on i386 Linux and on Sparc Solaris.

NOTE: My other project TinyCC which is a fully featured ISOC99 C compiler was written by starting from the source code of OTCC !

Compilation:

gcc -O2 otcc.c -o otcc -ldl
gcc -O2 otccelf.c -o otccelf

Self-compilation:

./otccelf otccelf.c otccelf1

4tH is a Forth compiler with a little difference. Instead of the standard Forth engine it features a conventional compiler.
4tH is a very small compiler that can create bytecode, C-embeddable bytecode, standalone executables, but also works fine as a scripting language. It supports over 85% of the ANS Forth CORE wordset and features conditional compilation, pipes, files, assertions, forward declarations, recursion, include files, etc.
It comes with an RPN calculator, line editor, compiler, decompiler, C-source generators, and a virtual machine.
Enhancements:
- More CORE words and most of the DOUBLE wordset are supported.
- Output buffers can be flushed.
- An experimental multitasking environment was added.

ObjectBox is a free, opensource o:XML compiler and interpretor written entirely in Java. ObjectBox o:XML Compiler implements The o:XML Programming Language specification, and provides a complete compilation and runtime environment.
Main features:
- Java extensions - o:XML procedure that converts any Java class/object to an o:XML type for seamless language integration, making existing Java classes instantly available for instantiation and subtyping as any other o:XML type.
- Java Servlet support for deployment in J2EE environments.
- Caching of compiled programs allowing threadsafe concurrent execution.
- Commandline executable that passes arguments to o:XML program.
- Java Ant task for powerful content generation and integration in XML publishing systems.
Before compilation the program file is parsed and validated for well-formedness. The result of compiling a program is an object hierarchy of actions, that will produce the program result as a sequential output to either a DOM tree, output stream or a SAX content handler.
In order to obtain a complete and fully valid XML document, the program must terminate successfully. However all o:XML programs dont necessarily terminate - see the Fibonacci Series for an example of a program that generates an infinite, unbroken XML stream.
A compiled o:XML program contains all parsed o:Path expressions and XML-generating objects. It is thread-safe and can execute concurrently in different runtime environments, producing output to different result handlers. The program in its compiled form is independent of the XML file it was generated from as well as the physical form of its output.
Version restrictions:
- Access Specifiers (public/private/protected) not fully implemented
- Context Node probably not always correct
Enhancements:
- Integration with the Spring 2.0 framework.
- Allows for the creation of o:XML beans in Spring 2.0.
- Full integration with support for XML schema configuration, and the ability to mix and match beans: o:XML, Java, JRuby, Groovy, Beanshell, etc.

Scriptol is an object oriented programming language designed to deliver the programmer from hardware or software constraints and let him or her concentrate only on the problem to formulate as a program.

Scriptol Compilers is universal, and allows building dynamic Web pages (with PHP as the backend), writing scripts, and building binary applications. It is compatible with Java and C++ libraries. Examples of use with PHP, Java, and GTK are included.

How to install the Java extension for Php or C++

1) Installing Java for Php
Search for the java path, example:
c:jdk1.4

Search for the php extensions path, example:
c:phpextensions

The extension directory must hold these files:
php_java.dll
php_java.jar

Set these lines into php.ini (in the Windows directory)
extension_dir = c:phpextensions
extension=php_java.dll

Search for the [java] section in php.ini - java.class.path must be assigned the path of all jar or class files including php_java.jar, separated by a semi-colon. (You can use a dot to designate the current path for yours jar or class file) - java.home

must be assigned the path of Java. - java.library
must be assigned the path of jvm.dll. - java.library.path
must be assigned the path of php extensions, that hold php_java.dll and php_java.jar and the path of any Java class you want to use.

- If these classes are inside jar files, the jar filenames are a part of the path.
- If several paths are required, they are separated by semicolons and enclosed in double quotes.

Example:
[Java]
java.class.path = "c:phpextensionsphp_java.jar;c:myclasses"
java.home = "c:jdk1.4"
java.library = "c:jdk1.4jrebinclientjvm.dll"
java.library.path = "c:phpextensions;c:jdk1.4jrelib"

2) Installing Java for Scriptol C++
- The jvm.dll must be in the path.
- The jvm.lib, jni.h, jni_md.h files must be in the directory of the source.
- The JAVA_HOME variable must be assigned the path of the JDK (ex: c:jdl1.4).
- See the README file if you encounter problems...

Java EDF files viewer is a multiplatform (Linux and Windows) EDF (European Data Format) files viewer written in Java and developped with Borland JbuilderX Foundation.
Usage
1. You need the Java software installed.
2. To execute the viewer
- type in command line: java -jar jEDF.jar
Enhancements:
- This release has hypnogram scoring, montage creation, spectral analysis, EEG event scoring, and a bilingual interface (English/French).

Scriptol to Php Compiler is a scriptol program that may be interpreted by the Php interpreter and it may be also compiled either to C++ or directly as an executable.

The Php interpreter is required by solp (download it at www.php.net or get it on the Scriptol CD).

Installation:

It is better to install Scriptol at root of a disk, for example:
/home/user/scriptolp

Once the archive is extracted into the scriptolp directory, you have just to go to this directory from the console to run the compiler.

To use the compiler at command line from any directory, you have to put the compilers into the path, in the usr directory for exemple, or any directory assigned to the path variable (see .bashrc or equivalent). You may also add the scriptol directory to list of paths. Before to use the compiler, you have to read the licence, in the doc directory: licence.html.

Usage:

Type the source of your program in a text editor and save it as mysource.sol or any other name with the sol extension.

Then just type:

./solp mysource

To know the compilers options, type solp without argument, at command line.

Examples:

Type from the main scriptol directory:
./solp demos/helloyou