How to generate JAXB classes from xsd

if there is any application server installed in the machine, in the bin directory one can find the xjc bat file. To generate classes

cmd>xjc PRPA_IN201310UV02.xsd -p com.covisint.cep.healthcare.hl7v3.pix.jaxb.response

where PRPA_IN201310UV02.xsd is the xsd file and the -p is the package under which the files needs to be generated.

The other options are as follows

OPTIONS

-nv

By default, the XJC binding compiler performs strict validation of the source schema before processing it. Use this option to disable strict schema validation. This does not mean that the binding compiler will not perform any validation, it simply means that it will perform less-strict validation.

-extension

By default, the XJC binding compiler strictly enforces the rules outlined in the Compatibility chapter of the JAXB Specification. Appendix E.2 defines a set of W3C XML Schema features that are not completely supported by JAXB v1.0. In some cases, you may be allowed to use them in the "-extension" mode enabled by this switch. In the default (strict) mode, you are also limited to using only the binding customizations defined in the specification. By using the "-extension" switch, you will be allowed to use the JAXB Vendor Extensions

-b

Specify one or more external binding files to process. (Each binding file must have its own "-b" switch.) The syntax of the external binding files is extremely flexible. You may have a single binding file that contains customizations for multiple schemas or you can break the customizations into multiple bindings files:

xjc schema1.xsd schema2.xsd schema3.xsd -b bindings123.xjb
xjc schema1.xsd schema2.xsd schema3.xsd -b bindings1.xjb -b bindings2.xjb -b bindings3.xjb

In addition, the ordering of the schema files and binding files on the command line does not matter.

-d

By default, the XJC binding compiler will generate the Java content classes in the current directory. Use this option to specify an alternate output directory. The output directory must already exist, the XJC binding compiler will not create it for you.

-p

Specifying a target package via this command-line option overrides any binding customization for package name and the default package name algorithm defined in the specification.

-httpproxy

Specify the HTTP/HTTPS proxy. The format is [user[:password]@]proxyHost[:proxyPort]. The old -host and -port are still supported by the RI for backwards compatibility, but they have been deprecated. Note that the password specified with this option is an argument that is visible to other users who use the top command, for example. For greater security, use -httpproxyfile, below.

-httpproxyfile

Specify the HTTP/HTTPS proxy using a file. Same format as above, but the password specified in the file is not visible to other users.

-classpath

Specify where to find client application class files used by the and customizations.

-catalog

Specify catalog files to resolve external entity references. Supports TR9401, XCatalog, and OASIS XML Catalog format. Please read the XML Entity and URI Resolvers document or the catalog-resolversample application.

-readOnly

By default, the XJC binding compiler does not write-protect the Java source files it generates. Use this option to force the XJC binding compiler to mark the generated Java sources read-only.

-npa

Supress the generation of package level annotations into **/package-info.java. Using this switch causes the generated code to internalize those annotations into the other generated classes.

-no-header

Supress the generation of a file header comment that includes some note and timestamp. Using this makes the generated code more diff-friendly.

-target 2.0

Avoid generating code that relies on any JAXB 2.1 features. This will allow the generated code to run with JAXB 2.0 runtime (such as JavaSE 6.)

-xmlschema

Treat input schemas as W3C XML Schema (default). If you do not specify this switch, your input schemas will be treated as W3C XML Schema.

-relaxng

Treat input schemas as RELAX NG (experimental, unsupported). Support for RELAX NG schemas is provided as a JAXB Vendor Extension.

-relaxng-compact

Treat input schemas as RELAX NG compact syntax(experimental, unsupported). Support for RELAX NG schemas is provided as a JAXB Vendor Extension.

-dtd

Treat input schemas as XML DTD (experimental, unsupported). Support for RELAX NG schemas is provided as a JAXB Vendor Extension.

-wsdl

Treat input as WSDL and compile schemas inside it (experimental,unsupported).

-quiet

Suppress compiler output, such as progress information and warnings.

-verbose

Be extra verbose, such as printing informational messages or displaying stack traces upon some errors.

-help

Display a brief summary of the compiler switches.

-version

Display the compiler version information.

Specify one or more schema files to compile. If you specify a directory, then xjc will scan it for all schema files and compile them.

Summary of Deprecated and Removed Command Line Options

-host & -port

These options have been deprecated and replaced with the -httpproxy option. For backwards compatibility, we will continue to support these options, but they will no longer be documented and may be removed from future releases.

-use-runtime

Since the JAXB 2.0 specification has defined a portable runtime, it is no longer necessary for the JAXB RI to generate **/impl/runtime packages. Therefore, this switch is obsolete and has been removed.

-source

The -source compatibility switch was introduced in the first JAXB 2.0 Early Access release. We have decided to remove this switch from future releases of JAXB 2.0. If you need to generate 1.0.x code, please use an installation of the 1.0.x codebase.

-Xlocator & -Xsync-methods

These switches have been disabled for now. We plan on releasing this functionality as a separate download in the future.

Changing Default GlassFish v3 Prelude Port Numbers 4848, 8080, and 8181 (The Open Road)

1. To change the HTTP port to 10080:
   
   asadmin set server.http-service.http-listener.http-listener-1.port=10080
   
   
2. To change the HTTPS port to 10443:
   
   asadmin set server.http-service.http-listener.http-listener-2.port=10443
   
   
3. To change the administration server port to 14848:
   
   asadmin set server.http-service.http-listener.admin-listener.port=14848
   

How To Fix LinkageError when using JAXB with JDK 1.6

If you run across an error like this when trying to use JAXB:

java.lang.LinkageError: JAXB 2.0 API is being loaded from the bootstrap classloader, but this RI
(from jar:file:/somedirectory/jaxb-impl.jar!/com/sun/xml/bind/v2/model/impl/ModelBuilder.class) needs 2.1 API. Use the endorsed directory mechanism to place jaxb-api.jar in the bootstrap classloader. (See http://java.sun.com/j2se/1.5.0/docs/guide/standards/)

This is apparently only a problem with JDK 1.6, not with JDK 1.5. It can be fixed by setting the JRE to 1.6.21 or 1.6.24 patches and not the 1.6 version

It can als be fixed by putting the jaxb-api.jar that you're trying to use into JDK_HOME/jre/lib/endorsed. If the endorsed directory doesn't exist, make it.

Error while configuring Jersey in JBOSS 5.1.0.GA

15:46:27,736 WARNING [AnnotatedClassScanner] URL, vfszip:/F:/Covisint HIE/jboss-5.1.0.GA/server/default/deploy/RestFulPrj.war/WEB-INF/classes/com/rest/cannot be converted to a URI

15:46:27,879 INFO [WebApplicationImpl] Initiating Jersey application, version 'Jersey: 1.1.1-ea-SNAPSHOT 07/13/2009 06:16 AM'

15:46:28,189 SEVERE [WebApplicationImpl] The ResourceConfig instance does not contain any root resource classes.

15:46:28,190 ERROR [[/RestFulPrj]] StandardWrapper.Throwable

com.sun.jersey.api.container.ContainerException: The ResourceConfig instance does not contain any root resource classes.

Are you deploying resources classes in a jar in WEB-INF/lib ?

The issue was fixed for the scheme of "vfsfile" but not for a scheme
of "vfszip".

Looking at the URL: vfszip:/F:/Covisint HIE/jboss-5.1.0.GA/server/default/deploy/RestFulPrj.war/WEB-INF/classes/com/rest/cannot be converted to a URI is a JBOSS propriety code to access the jar

This has been solved by adding all the jersey 1.3 snapshot jars instead of jersey 1.1.1 jars which i had previously from the loc http://download.java.net/maven/2/com/sun/jersey/

Difference between Strategy and Command Pattern

Typically the Command pattern is used to make an object out of what needs to be done -- to take an operation and its arguments and wrap them up in an object to be logged, held for undo, sent to a remote site, etc. There will tend to be a large number of distinct Command objects that pass through a given point in a system over time, and the Command objects will hold varying parameters describing the operation requested.

The Strategy pattern, on the other hand, is used to specify how something should be done, and plugs into a larger object or method to provide a specific algorithm. A Strategy for sorting might be a merge sort, might be an insertion sort, or perhaps something more complex like only using merge sort if the list is larger than some minimum size. Strategy objects are rarely subjected to the sort of mass shuffling about that Command objects are, instead often being used for configuration or tuning purposes.

Both patterns involve factoring the code and possibly parameters for individual operations out of the original class that contained them into another object to provide for independent variability. The differences are in the use cases encountered in practice and the intent behind each pattern.

Volatile Keyword

What does volatile do?

This is probably best explained by comparing the effects that volatile and synchronized have on a method. volatile is a field modifier, while synchronized modifies code blocks and methods. So we can specify three variations of a simple accessor using those two keywords:

         int i1;  
            int geti1() {return i1;} volatile int i2; 
             int geti2() {return i2;}          int i3; synchronized int geti3() {return i3;} 

geti1() accesses the value currently stored in i1 in the current thread. Threads can have local copies of variables, and the data does not have to be the same as the data held in other threads. In particular, another thread may have updated i1 in it's thread, but the value in the current thread could be different from that updated value. In fact Java has the idea of a "main" memory, and this is the memory that holds the current "correct" value for variables. Threads can have their own copy of data for variables, and the thread copy can be different from the "main" memory. So in fact, it is possible for the "main" memory to have a value of 1 for i1, for thread1 to have a value of 2 for i1 and for thread2 to have a value of 3 for i1 if thread1 and thread2 have both updated i1 but those updated value has not yet been propagated to "main" memory or other threads.

On the other hand, geti2() effectively accesses the value of i2 from "main" memory. A volatile variable is not allowed to have a local copy of a variable that is different from the value currently held in "main" memory. Effectively, a variable declared volatile must have it's data synchronized across all threads, so that whenever you access or update the variable in any thread, all other threads immediately see the same value. Of course, it is likely that volatile variables have a higher access and update overhead than "plain" variables, since the reason threads can have their own copy of data is for better efficiency.

Well if volatile already synchronizes data across threads, what is synchronized for? Well there are two differences. Firstly synchronized obtains and releases locks on monitors which can force only one thread at a time to execute a code block, if both threads use the same monitor (effectively the same object lock). That's the fairly well known aspect to synchronized. But synchronized also synchronizes memory. In fact synchronized synchronizes the whole of thread memory with "main" memory. So executing geti3() does the following:

1. The thread acquires the lock on the monitor for object this (assuming the monitor is unlocked, otherwise the thread waits until the monitor is unlocked).
2. The thread memory flushes all its variables, i.e. it has all of its variables effectively read from "main" memory (JVMs can use dirty sets to optimize this so that only "dirty" variables are flushed, but conceptually this is the same. See section 17.9 of the Java language specification).
3. The code block is executed (in this case setting the return value to the current value of i3, which may have just been reset from "main" memory).
4. (Any changes to variables would normally now be written out to "main" memory, but for geti3() we have no changes.)
5. The thread releases the lock on the monitor for object this.

So where volatile only synchronizes the value of one variable between thread memory and "main" memory, synchronized synchronizes the value of all variables between thread memory and "main" memory, and locks and releases a monitor to boot. Clearly synchronized is likely to have more overhead than volatile.

try with resource block

Often we use the try block while using resources like Streams and Connections. In these cases it is mandatory to close the resources after the completion of the task. We usually do the same in the finally block as in the example below

BufferedReader br = new BufferedReader(new FileReader(path));

try {

return br.readLine();

} finally {

br.close();

}

In Java 7 this process has been shortened by the try-with-resource statement. In this the resources are implicitly closed on the completion of the try fragment irrespective of whether the code was successfully executed or with exception. The only change is that the resource must implement the java.lang.AutoCloseable interface. The classes java.io.InputStream, OutputStream, Reader, Writer, java.sql.Connection, Statement, and ResultSet have been retrofitted to implement the AutoCloseable interface and can all be used as resources in a try-with-resources statement.