QuickJas

Multi-process Java application Server High performance Almost no special API

What's new in the current release of QuickJas

What is QuickJas

QuickJas is my new products with some friends. It is a multi-process (not multi-thread) Java application server. QuickJas is well designed for OLTP applications with many large size objects in a JVM of a huge heap. You might find that QuickJas could be the simplest Java application server. It utilizes non-invasive POJO classes as services and the users are not required to learn any special API to build a client/server system. QuickJas is written in pure java, however you can also use many native clients to call QuickJas services.

I have the plan to design such an application server long before, But my job is too busy for me to have spare time to write something. Now I am so happy that it is born. Till now I do not use any other project in QuickJas.

QuickJas is free to use except some tiny restrictions. Please consult the LICENSE.txt file in the top directory of QuickJas package.

Why Java?

My friends always think me as a C/C++ developer. But C/C++ is an error-prone language. I have been so tired to help customer developers to find their application problems. Java application is much easier to debug and it is also fast enough now.

Why Multi-Process?

I find all Java application servers using multi-thread because Java is not good at IPC. But if you use a very large heap and many large size objects in your Java applications, the performance of GC is very headache. This is why I created this project.

Installing QuickJas

You can expand QuickJas to any system directory and just use the bin/startJas or bin/stopJas script to start/stop QuickJas server. That's it, very easy.

The only thing that you may have to make sure of is that the "PATH" environment variable is set to hold the path of java executable. For example:
on Windows:
set PATH=C:\jdk1.5\bin;…
or on Unix:
% setenv PATH /usr/local/java:...
(csh)
$ PATH=/usr/java:...
export JAVA_HOME
(ksh, bash)

The bin/startJas or bin/stopJas script is very simple. It only set an environment variable named QUICK_JAS to point to the top directory of QuickJas. For example:
QUICK_JAS=D:\dev\java\QuickJas

Use following commands to start QuickJas:
bin\startJas.bat
or on Unix:
bin/startJas.sh

Use following commands to stop QuickJas:
bin\stopJas.bat
or on Unix:
bin/stopJas.sh

If you want to install multiple instances of QuickJas, note to change the ServicePort parameter in conf/QJMain.properties file to different values. The default value is 6080, which is the listening port of QuickJas to receive remote requests.

Configuring QuickJas

There is only configuration file named conf/QJMain.properties for QuickJas. I will introduce all parameters in the file as following:

Log.Level parameter specifies how much information to be logged. Note the following comment before it:
#0=OFF,1=SEVERE,2=WARNING,3=INFO,4=CONFIG,5=FINE,6=FINER,7=FINEST,8=ALL
The conceptions is according to JDK logging API.

JVMComandArguments parameter specifies the command line arguments to start Java application servers (JVM's).

AppServerNum parameter specifies how many Java application servers (JVM's) to be started to process the client requests.

CheckReqInterval parameter is related with performance for advanced users.

ServicePort parameter specifies the port number for QuickJas to wait client requests.

AdminSecret parameter specifies the password for QuickJas administration.

ServiceList parameter specifies the list of user application services. The format is "<Service name1>,<Service name2>,<Service name3>...".

<Service nameN> parameter specifies the full qualified class name of the user application service.

Something besides conf/QJMain.properties file for configuration is that it may be required to change the bin/startJas script, especially for CLASSPATH environment variable, to add something required by your application.

QuickJas Service Application Development

It is not required to learn any new API to write QuickJas service application. If you want to make your java code to be a QuickJas service, you should do as following:

• The service class must be public
• There must be 2 static methods in the java class:
  public static void init() // This method is invoked when QuickJas is started
  public static byte[] service(byte[] request) // This method is invoked every time when the client application call this service
  
• Change conf/QJMain.properties file to set service name and full qualified class name of the service.
• Change CLASSPATH environment variable in the bin/startJas script to add something required by your application.

You can find sample service applications in the sample directory. There are 3 sample user services defined in conf/QJMain.properties file. To test the services, you can run bin/test* scripts. Those sample applications are also included in lib/QuickJas.jar file.

QuickJas Client Application Development

It is only required for you to learn only one interface named JasClient with one method named invokeService to call QuickJas services. The method invokeService is defined as following:
byte[] invokeService(java.lang.String server, int port, java.lang.String service, byte[] data) throws JasException, java.io.IOException

This is the entry to access QuickJas service

Parameters:
server - The QuickJas server name or IP address
port - The QuickJas server listening port
service - The QuickJas service name
data - The input data

Returns:
The return value of the service

Throws:
JasException, java.io.IOException


Use following code to create a JasClient object:
lr.quickjas.app.JasClient jc = lr.quickjas.app.JasService.createJasClient();

You can find sample client applications also including many native clients samples in the sample directory. There are 3 sample user services defined in conf/QJMain.properties file. To test the services, you can run bin/test* scripts. Those sample applications are also included in lib/QuickJas.jar file.

Thanks you for your interest in QuickJas. I welcome all feedback at liurui@lrsolution.com.