Free java runtime environment software for linux

Java 2SE technology readily harnesses the power of the network because it is both a programming language and a selection of specialized platforms.
As such, it standardizes the development and deployment of the kind of secure, portable, reliable, and scalable applications required by the networked economy.
Because the Internet and World Wide Web play a major role in new business development, consistent and widely supported standards are critical to growth and success.
The Java programming language lets you write powerful, enterprise-worthy programs that run in the browser, from the desktop, on a server, or on a consumer device. Java programs are run on -- interpreted by -- another program called the Java Virtual Machine (Java VM).
Rather than running directly on the native operating system, the program is interpreted by the Java VM for the native operating system. This means that any computer system with the Java VM installed can run a Java program regardless of the computer system on which the application was originally developed.
The Java platform is a software-only platform that runs on top of other hardware-based platforms. Because hardware-based platforms vary in their storage, memory, network connection, and computing power capabilities, specialized Java platforms are available to address applications development for and deployment to those different environments.
Java technology has grown to include the portfolio of specialized platforms listed below. Each platform is based on a Java VM that has been ported to the target hardware environment. This means, for example, in the case of Desktop Java, desktop applications written in the Java programming language can run on any Java VM-enabled desktop without modification.
Java 2 Platform, Standard Edition (J2SE), provides an environment for Core Java and Desktop Java applications development, and is the basis for Java 2 Platform, Enterprise Edition (J2EE) and Java Web Services technologies. It has the compiler, tools, runtimes, and Java APIs that let you write, test, deploy, and run applets and applications.
Enhancements:
- Olson time zone data was updated to version 2007e.
- Solaris-specific I/O interruption in response to thread interruption can now be switched off.
- Many bugs were fixed.

The Java Binary Enhancement Tool (JBET) is a general Java program analysis and manipulation tool. Existing class files can be disassembled, reassembled, or edited programmatically through the JBET API. JBET can also be used to create new Java class files from scratch. JBET uses a convenient internal representation of all the contents of Java binary (.class) files, allowing the user to edit the classes easily, in a structured manner.

JBET was developed as part of the DARPA Self-Protecting Mobile Agents project under the OASIS and Active Networks programs (contract number N66001-00-C-8602) in order to study automated software obfuscation.

The Java language was chosen for this project because of the (relative) ease of constructing binary editing tools provided by the large amount of type information present in the class files. Our two reports, the Obfuscation Techniques Evaluation Report, and the Obfuscation Report, are available from the download area. The obfuscation tool developed is not part of this release.

JBET was also used in the DARPA/AFRL Survivable Server project (contract number F30602-00-C-0183) to add additional security checks to the Java Standard Library. (The Java SecurityManager API does not support many desirable security checks, such as continued authorization of file accesses after opening.)

JBET was used to replace the native method references in the Java standard library with stubs that call a pluggable security policy. This tool, called Jpolicy, is also available for download at this website. Jpolicy is very incomplete at this time, but may be interesting to those working in Java security or changing the standard library themselves.

The internal representation of Java class files used by JBET is intented to make it easy for programmers to write Java binary code transforms. Each element of Java class files has a corresponding internal data structure: ClassInfo for entire classes, MethodInfo for methods, FieldInfo for fields, Snippit for code blocks, and Instruction for individual instructions. Snippit and Instruction understand Java opcode syntax and semantics, allowing automated creation of valid Java programs. A Java-compatible class verifier is also included.

Some code transforms are difficult to program directly by manipulating Java instructions. For those transforms, a directed acyclic graph (DAG) representation of code is available. In the DAG representation, each basic block has a corresponding DAG, with a set of input and output nodes. Edges in the graph connect "producer" nodes (such as constants, or the result of calculations) to "user" nodes (such as method calls or other calculations). Methods are divided into basic blocks and control flow is stored at the basic block level (possible because Java has only fixed jump targets)

JBET requires a Java 1.4 virtual machine to run, although it can operate on class files from earlier Java versions. The packaging and build environment supplied supports Linux and Windows with Cygwin; however, the build process is simple and could be performed manually on other platforms. Perl is required for regression testing.

Jpolicy requires a Java 1.4 virtual machine to build, either Linux or Windows NT/XP with Cygwin. gcc is required for building on Windows (supplied with Cygwin). The runtime system can be either Java 1.3 or 1.4 (with Suns JVM only), running on Linux or Windows NT/XP. Windows 9x and Windows 2000 may work as well, but have not been tested.

Installation

1. Install jdk 1.4.1.
2. Set CLASSPATH to jdk1.4.1/jre/lib/rt.jar
3. cd src; make
4. If that didnt work, examine the makefile. java or javac may not be in the path.
5. To build a jar file that can be used with "java -jar jbet.jar", run "make jar".
6. If you have perl installed, run the tests with "make test".
Optionally, run "make regen; make test".

Make a symbolic link from jbet3/bin/jbet to somewhere in your path.

Usage

JBET uses the JNI format for class names, and JNI type and method descriptors. For a summary of this syntax, use jbet help syntax. Suns JVM specification may also be helpful.

To look at a class disassembly, use jbet print. Try disassembling a class you have source for, and was built with debug info (-g): jbet -P < classpath > print < classname >. Suns JVM specification has an instruction reference.

The Java Brainfuck Compiler is a compiler for the uniquely powerful Brainfuck language, which produces Java bytecode that will run on any Java Virtual Machine (with no intermediate steps such as going by way of Java code).

Bitgate Server Software Environment aims to build a multi-protocol environment in which server protocol handlers can be eventually loaded and unloaded on the fly using a center console or controller Web page.
Bitgate Server Software Environment aims to have 99.9% uptime, and have high-availability (Java 6) compliance. It is written in Java 5, and relies completely on Javas I/O functionality to provide non-blocking support for both SSL and non-SSL sockets (transparently).
All configuration is done via XML files, as this is easier to maintain. It includes a minimal demonstration HTTP server.
Enhancements:
- Modified HTTP directory listing to be a little more clean on the output of filenames; shows more information about each file in question as well.
- Added "reset" methods to the ClientContext objects so that Keep-Alive requests are now handled properly.
- Implemented 302 redirects and space encodings on filenames.

Java-GNOME application is a set of Java bindings for the GNOME and GTK libraries that allow GNOME and GTK applications to be written in Java.

The Java-Gnome API has been carefully designed to be easy to use, maintaining a good OO paridigm, yet still wrapping the entire functionality of the underlying libraries.

Java-Gnome can be used with the Eclipse development environment and Glade user interface designer to create applications with ease.

Java-Gnome is part of the official Gnome Bindings Release, commiting us to high quality regular releases.

Java Embedded Python embeds CPython in Java. It is safe to use in a heavily threaded environment, it is quite fast and its stability is a main feature and goal.
Main features:
- Using the native Python interpreter may mean a massive speed improvement over Java-based languages.
- Python is mature so authors neednt fear the interpreter will suddenly change widely-used features.
- Access to the high quality Python modules, both native and Python-based.
- Compilers and assorted Python tools are as mature as the language.
- Python is an ideal language for your business logic. It is easy to learn, eminently readable and generally immune to programming gotchas.
Patches, comments and other help is greatly appreciated. If you need help, post to the SourceForge mailing list or forums. Please include code snippets for the most accurate response.

Java Tools is a lightweight integrated development environment for creating, compiling, and executing Java applications and applets.
Java Tools includes point and click access to the Java files, commands, and documents. It also includes a built-in text editor and user interface for the Java debugger.
It is intended for the new Java user who needs help getting started. Its also for the more experienced Java user who wants easy access to the Java commands and a text editor.
Main features:
- GUI with built-in help and small footprint.
- Point and click access to all files (Java, manifest, HTML, image and sound) and directories (package).
- Point and click access to all commands for compiling (javac), archiving (jar), documenting (javadoc), executing (java), debugging (jdb) and disassembling (javap).
- Point and click access to all documents (Java API Specification, Java Tools and Utilities, Java Features and Java Tutorial).
- Point and click creation of all files (Java, manifest and HTML) and directories (package).
- Point and click installation of distribution archive files (Java document, Java source code, Java Tutorial and Sun Tools).
- Automatic determination of class file dependencies for archiving (jar) and documenting (javadoc) Java files.
- Checking for unused, redundant and missing imports.
- Logging of all commands invoked by GUI.
- Code metrics for Java files.
- Built-in text editor (see Edit for details).
- Built-in user interface for the Java debugger with command-line editing and history.
- Self-installing executable (Java archive file).
- Comprehensive installation and user documentation for Java and Java Tools.