Free java bytecode 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

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.

Jabber is an instant messagings system (and a few other things but Ill forget about these for the moment), but it uses XML so its easy to create clients for it, and to link it in with other systems.

As well as that anyone can run a Jabber server, so youre school, university or office could have their own messaging system.

Java Bomberman project is a multiplayer game for Java.

Instructions

First of all start a bomberman server by typing...

# java BombermanServer [-port 1033 -speed 3 -timeout 300]

You can use the -port option to change the default port number.

You the -speed option to change the player speed at game start (default 3). The option -timeout changes the timeout (default 300).

After the server has started successfully you can start several clients by typing...

# java BombermanClient [-name nickname -port 1034
-host 127.0.0.1 -serverport 1033
-quiet
-music
-theme ice
-x 0 -y 0
-c1 16756655 -c2 16776960
-ai BombermanDefaultAI
-i]

Java Web Shell is a web based interactive shell-type environment written in Java.

Obviously, to use the shell, youll need to be using a browser that supports Java Applets, and this has been compiled using the Sun 1.4.1 JDK.

Head over to Sun and pick up the latest runtime enviroment if you dont already have it.

Java for C++ is a tool to generate C++-wrapper-classes for existing Java-classes. This tool reads a list of Java class names and creates source code for C++-classes to wrap them.
The implementation of the wrapper classes uses JNI (Java Native Interface) to call the "real" Java classes.
The C++-API to use these wrapper classes is very close to the API of the original Java classes. So developers of C++-software can use Java-classes as if they have been implemented in C++.
Enhancements:
- A problem where null values for method arguments, method return values, or field values caused some generated code to crash was fixed.
- Updating is strongly encouraged.

Java Properties provides an efficient way to access bean-like properties of Java objects.

In a nutshell, provides an efficient way to access bean-like properties of java objects. Unlike java bean properties, a chain of properties can be specified efficiently, allowing convenient access to properties of nested domain objects.

Runtime class-generation and caching can be used very easily to obviate the need for reflection, without losing the flexibility it provides.

Class Properties It also provides classes which manipulate objects at runtime by using strings to address conceptual variables (think bean properties) in a similar fashion to the java reflection mechanisms.

Class Property example Say we have the following classes:

public class Order {
...
public Customer getCustomer() { ... }
...
}
public class Customer {
...
public Address getAddress() { ... }
...
}
public class Address {
...
public String getLine1() { ... }
public String getLine2() { ... }
...
}

Now, we could do this to access line 1 of the address:

result = order.getCustomer().getAddress().getLine1();

But what if there are nulls? What if we want to compare the first line of the address from two different orders? Whith properties this is really simple:

ClassProperty p = PropertyManager.getProperty(Order.class,"Customer:Address:Line1",true);
result = p.getValue(order);

The idea is simple enough - you use the string "Customer:Address:Line1" to specify a series of getXXX calls. Importantly, it the library handles nulls for you, returning null if any of the objects in the chain are null.

Note, this is not simply a wrapper around java reflection, since it includes non-reflective optimizations by making use of the cojen library to generate class files at runtime to acces these properties.

The real benefit lies in being able to specify which properties you wish to access at runtime. You can even pass this ability on to the users of your library or application. Unlike reflection, class files are generated for the properties, and these files are cached - which means once you have specified a property once, further uses of the same property dont use reflection and are very fast.

Property API vs Java Bean Properties. The property API models accessor/mutator method pairs as conceptual variables called properties. The approach used is similar to, but more flexible than java bean properties, and more performant than reflection if runtime class generation is used. Unlike java bean properties, a chain or path of properties can be specified (and more importantly, turned into bytecode using runtime generation) to traverse a complex tree of objects.
It is simple to create applications portable between different security environments - using runtime generation where allowed, and falling back to reflection where security is tighter.

Dynamic Class Management. The properties package also provides classes to handle the loading (and unloading/reloading) of classes at runtime. It provides a framework useful for dynamically loading runtime-generated classes, for example.
While the property API can happily ignore the dynamic loading framework, it can also make use of it to enable runtime class generation.