Free java class software for linux

ProGuard is a free Java class file shrinker, optimizer, and obfuscator. ProGuard project can detect and remove unused classes, fields, methods, and attributes. It can then optimize bytecode and remove unused instructions.
Finally, it can rename the remaining classes, fields, and methods using short meaningless names. The resulting jars are smaller and harder to reverse-engineer.
More compact jar files also means smaller storage requirements, faster transfer of applications across networks, faster loading, and smaller memory footprints.
ProGuards main advantage compared to other Java obfuscators is probably its compact template-based configuration. A few intuitive command line options or a simple configuration file are usually sufficient. For instance, the following configuration option preserves all applets in a jar:
-keep public class * extends java.applet.Applet
The user manual explains all available options and shows more examples of this powerful configuration style.
ProGuard is fast. It only takes seconds to process programs and libraries of several megabytes. The results section presents actual figures for a number of applications.
ProGuard is a command-line tool with an optional graphical user interface. It also comes with plugins for Ant and for the J2ME Wireless Toolkit.
ProGuard is a Java class file shrinker, optimizer, and obfuscator. The shrinking step detects and removes unused classes, fields, methods, and attributes. The optimization step analyzes and optimizes the bytecode of the methods. The obfuscation step renames the remaining classes, fields, and methods using short meaningless names. The resulting jars are smaller and harder to reverse-engineer.
ProGuard can also be used to list unused fields and methods in an application, and to print out the internal structure of class files.
ProGuard typically reads the input jars (or wars, ears, zips, or directories). It then shrinks, optimizes, and obfuscates them. It then writes the results to one or more output jars (or wars, ears, zips, or directories). The input jars can optionally contain resource files. ProGuard copies all non-class resource files from the input jars to the output jars. Their names and contents remain unchanged.
ProGuard requires the library jars (or wars, ears, zips, or directories) of the input jars to be specified. It can then reconstruct class hierarchies and other class dependencies, which are necessary for proper shrinking, optimization, and obfuscation. The library jars themselves always remain unchanged. You should still put them in the class path of your final application.
In order to determine which code has to be preserved and which code can be discarded or obfuscated, you have to specify one or more entry points to your code. These entry points are typically classes with main methods, applets, midlets, etc.
- In the shrinking step, ProGuard starts from these seeds and recursively determines which classes and class members are used. All other classes and class members are discarded.
- In the optimization step, ProGuard further optimizes the code. Among other optimizations, classes and methods that are not entry points can be made final, and some methods may be inlined.
- In the obfuscation step, ProGuard renames classes and class members that are not entry points. In this entire process, keeping the entry points ensures that they can still be accessed by their original names.
Any classes or class members of your code that are created or invoked dynamically (that is, by name) have to be specified as entry points too. It is generally impossible to determine these cases automatically, but ProGuard will offer some suggestions if keeping some classes or class members appears necessary. For proper results, you should at least be somewhat familiar with the code that you are processing.
ProGuard does handle Class.forName("SomeClass") and SomeClass.class constructs automatically. The referenced classes are preserved in the shrinking phase, and the string arguments are properly replaced in the obfuscation phase. With variable string arguments, it is generally impossible to determine their possible values (they might be read from a configuration file, for instance).
However, as mentioned, ProGuard will note constructs like "(SomeClass)Class.forName(variable).newInstance()". These might be an indication that the class or interface SomeClass and/or its implementations may need to be preserved. You can then adapt your configuration accordingly.
Whats New in 3.9 Stable Release:
- This release fixes a number of bugs.
- Notably, ".class" constructs compiled in Java 6 are now handled correctly.
- The optimization step now avoids a possible division by 0 and correctly processes local variables with indices larger than 255.
- The documentation and examples have been updated.
Whats New in 4.0 Beta Development Release:
- Added preverifier for Java 6 and Java Micro Edition, with new option -dontpreverify.
- Added new option -target to modify java version of processed class files.
- Made -keep options more orthogonal and flexible, with option modifiers allowshrinking, allowoptimization, and allowobfuscation.
- Added support for configuration by means of annotations.
- Improved shrinking of unused annotations.
- Added check on modification times of input and output, to avoid unnecessary processing, with new option -forceprocessing.
- Added new options -flattenpackagehierarchy and -repackageclasses (replacing -defaultpackage) to control obfuscation of packages names.
- Added new options -adaptresourcefilenames and -adaptresourcefilecontents, with file filters, to update resource files corresponding to obfuscated class names.
- Now respecting naming rule for nested class names (EnclosingClass$InnerClass) in obfuscation step, if InnerClasses attributes or EnclosingMethod attributes are being kept.
- Added new inter-procedural optimizations: method inlining and propagation of constant fields, constant arguments, and constant return values.
- Added optimized local variable allocation.
- Added over 250 new peephole optimizations.
- Improved making classes and class members public or protected.
- Now printing notes on suspiciously unkept classes in parameters of specified methods.
- Now printing notes for class names that dont seem to be fully qualified.
- Added support for uppercase filename extensions.
- Rewritten class file I/O code.
- Updated documentation and examples.

Polyglot is a highly extensible compiler front end for the Java programming language. The project is implemented as a Java class framework using design patterns to promote extensibility. Using Polyglot, language extensions can be implemented without duplicating code from the framework itself.
Polyglot has been used to implement domain-specific languages, to explore language design ideas, to simplify Java for pedagogical purposes, and for various code transformations such as optimization and fault injection. Polyglot has been used for both major and minor language extensions; our experience suggests that the cost of implementing an extension scales well with the degree to which it modifies Java.
Polyglot compiles and runs on (at least) Linux, Solaris, Windows, and Mac OS X. Ant and the JFlex scanner generator are required to build it. On Windows, you will also need Cygwin.
Polyglot includes PPG, an extensible LALR parser generator based on the CUP LALR parser generator for Java (extended with improved debugging support).
Polyglot supports Java version 1.4, but a Polyglot extension that supports Java 5. has been developed at UCLA.
A version of Polyglot written in the J& language is also under development. It makes extending the base compiler even easier.
Enhancements:
- Miscellaneous bugfixes.
- An assumption that return statements occur only within methods has been fixed.
- A copy(NodeFactory) method has been added to the Node interface to generate a new version of a node with a different node factory.

RJCE allows all methods or variables of user defined classes to be altered at runtime. These alterations are then applied to a single instance, a collection of instances (i.e. list, set or map), or an entire class.

This helps you to test your application in an interactive way; altering running programs helping a trial and error approach to programming; testing code and saving it when it’s correct. Long running algorithms, such as simulations, can also easily be refined without the need for restarts or lose of data.

RJCE can be used to write a program from within itself ensuring high coupling between testing and development, with no delay before the outcome of any alterations.

RJCE allows scripts to run from within your application, allowing users to configure or extend an application dynamically, bypassing normal language access rules controlled by public, private and protected. This can be done by easily instatiating an instance of CodeEditorFrame from the rom.gui package.

RJCE permits faster development of applications by allowing easy migration from scripts to Java programs.

DateChooser is a Java class that allows a programmer to present the user with an input dialog for easily choosing a date and feeding it to the program.

java-diff is a set of Java classes which implement the longest common subsequences algorithm.

java-diff compares the elements in two arrays, returning a list of Difference objects, each of which describes an addition, deletion, or change between the two arrays.

UDoc is a tool to visualize some Java classes. UDoc dynamically produces some UML-like diagrams from various sources (Javadoc, Java sources, Java binaries).

The diagrams contain a lot of information, and you can easily navigate from classes to classes.

jclassinfo reads java class files and provides information about the class, dependencies and more. It is a pure C implementantion.
Main features:
Class Information
- Java VM version required,
- super class,
- interfaces implemented. --general-info
- Constant pool dump --constant-pool
- Methods --methods
- Fields --fields
- Class attributes --attributes
Dependency Information
- Packages required --packages
- Classes required --classes
- Methods required --methods-ref
Options affecting verbosity
- Disassemble code --disasm
- Print limits and exception table for methods --verbose
- Print debugging information --method-debug-info
- Change visibility --visibility=< public | package | protected | private | synthetic >

Java::Import::Examples is an example of how to use Java::Import to call into Java classes.

Making RMI calls from Perl

One nice thing about Java is the extremely straight forward manner in which it allows you to make calls to remote objects residing on distant servers. Many people use this ability as a point of integration between their system and a posible third party or legacy system. Unfortunatly, for the most part the ability to make calls to these remote objects is something that only other Java applications can do without making a big fuss about it. However, we can now do this from Perl.

Assume that I have a RMI server from which I can get data from in the form of simple Java Beans. One method of doing this is to use the GCJ::Cni library and natively compile and wrap a set of Java Classes which can then be used from my Perl script. However, there is an easier way.

Lets begin by descriping the Java interfaces that well be working with. We first have the Remote Interface that we will be interacting with:

import java.rmi.*;
public interface RemoteInterface extends Remote {
public SomeBean getMessage(String seedMessage) throws RemoteException;
}
And we also have the bean we will be asking for:
import java.io.*;
public class SomeBean implements Serializable {
private String value;
public SomeBean() {}
public void setValue ( String _value ) { ... }
public String getValue ( ) { ... }
}
As far as any Perl client program is concerned this is all we need to know about.
Now all there is left to do is write a client:
use Java::Import qw(
java.rmi.Naming
);

my $remote_interface = java::rmi::Naming->lookup(jstring("//localhost/Home"));
my $bean = $remote_interface->getMessage(jstring("Hi there"));
print $bean->getValue(), "n";

Thats all there is. Notice that all we had to tell Java::Import about was java.rmi.Naming, this is because it was the only class we used by name in our Perl code, every other Java class (the objects held by $bean and $remote_interface) was returned by some other method call originating from java.rmi.Naming.

In order to run this example we have to make sure everything is in its place. We start by compiling the client code. Assuming that we have been given a Stub class file (RemoteObject_Stub.class) we can do the following:

gcj -C SomeBean.java RemoteInterface.java
fastjar -cvf client.jar SomeBean.class RemoteInterface.class RemoteObject_Stub.class

Making sure our server is reachable we can then run the client code:

CLASSPATH=client.jar perl client.pl

Thats it, you should then see the message returned by your server.