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Foreword: Excuse me for
possible mistakes. English is not native language for me.
In this issue:
Hello dear friends!
Question: The class Robot was introduced in Java
version 1.3 and belongs to awt (java.awt.Robot). Why? I got an impression that
all new GUI features come to Swing and Robot class is GUI related
Answer: The reason is simple: The Swing toolkit is a
fully-featured UI component library implemented entirely in the Java programming
language. The Robot class is used to generate native system input events for the
purposes of test automation, self-running demos, and other applications where
control of the mouse and keyboard is needed. The primary purpose of Robot is to
facilitate automated testing of Java platform implementations.
Using the class to generate
input events differs from posting events to the AWT event queue or AWT
components in that the events are generated in the platform's native input
queue. For example, Robot.mouseMove will actually move the mouse cursor instead
of just generating mouse move events.
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Question: What is jvmstat?
Answer: The jvmstat technology adds light weight
performance and configuration instrumentation to the HotSpot JVM and provides a
set of monitoring APIs and tools for monitoring the performance of the HotSpot
JVM in production environments. The instrumentation is designed such that it is
'always on', yet has negligible performance impact. The monitoring interfaces
added to the HotSpot JVM are proprietary and may or may not be supported in
future versions of the HotSpot JVM.
Tools include a general
purpose command line tool called jvmstat, a java process list tool called jvmps,
and a generational heap visualization tool called visualgc. Remote monitoring is
supported via an RMI server application.
The instrumented HotSpot JVM
shipped with J2SE 1.4.1 as a technology preview. The instrumentation is disabled
by default, but can be easily enabled through a command line argument. The tools
included with this distribution can only monitor Java applications running on
the HotSpot 1.4.1 JVM as distributed with Sun's J2SE 1.4.1
The jvmstat feature includes
a number of tools:
jvmstat - A tool to sample
and log instrumentation
jvmps - A tool providing a
simple Java process listing
visualgc - A tool to
graphically display instrumentation
perfagent - A server
providing remote access to instrumentation
tip is based on
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Question: What type of garbage collection does a
Answer: An explicit request to do a garbage collection
does a full collection (both young generation and tenured generation). A full
collection is always done with the application paused for the duration of the
Latest posts on our
|Compositing(image and movie) in
I would like to do some
compositing in Java. Currently I'm using QuickTime for Java to do it. It is very
easy. However I always get some runtime exception when I execute the program. So
I want to switch to pure Java. I want to play a movie as the background,
probably using JMF. Then do some animation with some images and text in front of
the movie. Is this possible? Any advice or sample program?
Thanks in advance.
|JTabbedPane and focus issue
Maybe I'm just doing things a
bit different than anyone else and I'm wrong. Here's the deal: I have a focus
traversal policy for each frame in my app. When I used a personally-created
subclass of JTabbedPane it was trying to set focus on a component on a
non-visible tab. So I fixed that problem by not allowing focus to go to
non-visible tab panels.
Now I want, on a tab change, to set focus on the
first focusable component of the new tab. But at the time I get a change event
to hook this call the old tab is still visible and the second one isn't.
So my first fix...
|How to realize my project
I’m new on java and i
should do a project to create an application to design Workflow on thin client
(IE6) or a software and use Java Web Start. The design is base on the
state-chart diagram. All the information concerning items (position, size) will
be store under lotus Notes Documents.
Each item (state, chart relations)
will have different values selected from list. Each list will be fill in with
informations descended from data contains under Lotus Notes documents.
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