idlj - The IDL-to-Java Compiler

idlj generates Java bindings from a given IDL file.


idlj [ options ] idl-file

where idl-file is the name of a file containing Interface Definition Language (IDL) definitions. Options may appear in any order, but must precede the idl-file.


The IDL-to-Java Compiler generates the Java bindings for a given IDL file.  For binding details, see the OMG IDL to Java Language Language Mapping Specification. Some previous releases of the IDL-to-Java compiler were named idltojava.

Emitting Client and Server Bindings

To generate Java bindings for an IDL file named My.idl: This generates the client-side bindings and is equivalent to: The client-side bindings do not include the server-side skeleton. If you want to generate the server-side bindings for the interfaces: Server-side bindings include the client-side bindings plus the skeleton, all of which are POA (that is, Inheritance Model) classes. If you want to generate both client and server-side bindings, use one of the following (equivalent) commands:

There are two possible server-side models: the Inheritance Model and the Tie Delegation Model.

NEW in 1.4! The default server-side model is the Portable Servant Inheritance Model. Given an interface My defined in My.idl, the file is generated. You must provide the implementation for My and it must inherit from MyPOA. is a stream-based skeleton that extends org.omg.PortableServer.Servant and implements the InvokeHandler interface and the operations interface associated with the IDL interface the skeleton implements.

The PortableServer module for the Portable Object Adapter (POA) defines the native Servant type. In the Java programming language, the Servant type is mapped to the Java org.omg.PortableServer.Servant class. It serves as the base class for all POA servant implementations and provides a number of methods that may be invoked by the application programmer, as well as methods which are invoked by the POA itself and may be overridden by the user to control aspects of servant behavior.

Another option for the Inheritance Model is to use the -oldImplBase flag in order to generate server-side bindings that are compatible with older version of the Java programming language (prior to J2SE 1.4). Note that using the -oldImplBase flag is non-standard: these APIs are being deprecated. You would use this flag ONLY for compatibility with existing servers written in J2SE 1.3. In that case, you would need to modify an existing MAKEFILE to add the -oldImplBase flag to the idlj compiler, otherwise POA-based server-side mappings will be generated. To generate server-side bindings that are backwards compatible:

Given an interface My defined in My.idl, the file is generated. You must provide the implementation for My and it must inherit from _MyImplBase.

The other server-side model is called the Tie Model. This is a delegation model. Because it is not possible to generate ties and skeletons at the same time, they must be generated separately. The following commands generate the bindings for the Tie Model:

For the interface My, the second command generates The constructor to MyPOATie takes a delegate. In this example, using the default POA model, the constructor also needs a poa. You must provide the implementation for delegate, but it does not have to inherit from any other class, only the interface MyOperations. But to use it with the ORB, you must wrap your implementation within MyPOATie. For instance: You might want to use the Tie model instead of the typical Inheritance model if your implementation must inherit from some other implementation. Java allows any number of interface inheritance, but there is only one slot for class inheritance. If you use the inheritance model, that slot is used up . By using the Tie Model, that slot is freed up for your own use. The drawback is that it introduces a level of indirection: one extra method call occurs when invoking a method.

To generate server-side, Tie model bindings that are compatible with older version of the IDL to Java language mapping in versions of J2SE before 1.4.

For the interface My, this will generate The constructor to My_Tie takes a impl. You must provide the implementation for impl, but it does not have to inherit from any other class, only the interface HelloOperations. But to use it with the ORB, you must wrap your implementation within My_Tie. For instance:

Specifying Alternate Locations for Emitted Files

If you want to direct the emitted files to a directory other than the current directory, invoke the compiler as:
idlj -td /altdir My.idl
For the interface My, the bindings will be emitted to /altdir/, etc., instead of ./

Specifying Alternate Locations for Include Files

If My.idl included another idl file, MyOther.idl, the compiler assumes that MyOther.idl resides in the local directory. If it resides in /includes, for example, then you would invoke the compiler with the following command: If My.idl also included Another.idl that resided in /moreIncludes, for example, then you would invoke the compiler with the following command: Since this form of include can become irritatingly long, another means of indicating to the compiler where to search for included files is provided. This technique is similar to the idea of an environment variable. Create a file named idl.config in a directory that is listed in your CLASSPATH. Inside of idl.config, provide a line with the following form: The compiler will find this file and read in the includes list. Note that in this example the separator character between the two directories is a semicolon (;). This separator character is platform dependent. On NT it is a semicolon, on Solaris it is a colon, etc. For more information on includes, read the CLASSPATH (Solaris) or CLASSPATH (Windows) documentation.

Emitting Bindings for Include Files

By default, only those interfaces, structs, etc, that are defined in the idl file on the command line have Java bindings generated for them. The types defined in included files are not generated. For example, assume the following two idl files: The following command will only generate the java bindings for My: To generate all of the types in My.idl and all of the types in the files that My.idl includes (in this example, MyOther.idl), use the following command: There is a caveat to the default rule. #include statements which appear at global scope are treated as described. These #include statements can be thought of as import statements. #include statements which appear within some enclosing scope are treated as true #include statements, meaning that the code within the included file is treated as if it appeared in the original file and, therefore, Java bindings are emitted for it. Here is an example: Running the following command: will generate the following list of Java files: Notice that was not generated because it is defined in an import-like #include. But was generated because it was defined in a true #include. Also notice that since Embedded.idl was included within the scope of the interface My, it appears within the scope of My (that is,in MyPackage).

If the -emitAll flag had been used in the previous example, then all types in all included files would be emitted.

Inserting Package Prefixes

Suppose that you work for a company named ABC that has constructed the following IDL file: Running this file through the IDL-to-Java compiler will place the Java bindings for W1 and W2 within the package Widgets. But there is an industry convention that states that a company's packages should reside within a package named com.<company name>. The Widgets package is not good enough. To follow convention, it should be To place this package prefix onto the Widgets module, execute the following: If you have an IDL file which includes Widgets.idl, the -pkgPrefix flag must appear in that command also. If it does not, then your IDL file will be looking for a Widgets package rather than a package.

If you have a number of these packages that require prefixes, it might be easier to place them into the idl.config file described above. Each package prefix line should be of the form:

So the line for the above example would be:

The use of this option does not affect the Repository ID.

Defining Symbols Before Compilation

You may need to define a symbol for compilation that is not defined within the IDL file, perhaps to include debugging code in the bindings. The command is the equivalent of putting the line #define MYDEF inside My.idl.

Preserving Pre-Existing Bindings

If the Java binding files already exist, the -keep flag will keep the compiler from overwriting them. The default is to generate all files without considering if they already exist. If you've customized those files (which you should not do unless you are very comfortable with their contents), then the -keep option is very useful. The command emit all client-side bindings that do not already exist.

Viewing Progress of Compilation

The IDL-to-Java compiler will generate status messages as it progresses through its phases of execution. Use the -v option to activate this "verbose" mode: By default the compiler does not operate in verbose mode.

Displaying Version Information

To display the build version of the IDL-to-Java compiler, specify the -version option on the command-line:

idlj -version

Version information also appears within the bindings generated by the compiler. Any additional options appearing on the command-line are ignored.


-d symbol
This is equivalent to the following line in an IDL file:
#define symbol

Emit all types, including those found in #include files.

Defines what bindings to emit. side is one of client, server, serverTIE, all, or allTIE. The -fserverTIE and -fallTIE options cause delegate model skeletons to be emitted. Assumes -fclient if the flag is not specified.

-i include-path
By default, the current directory is scanned for included files. This option adds another directory.

If a file to be generated already exists, do not overwrite it. By default it is overwritten.

Suppresses warning messages.

Generates skeletons compatible with old (pre-1.4) JDK ORBs. By default, the POA Inheritance Model server-side bindings are generated. This option provides backward-compatibility with older versions of the Java programming language by generating server-side bindings that are ImplBase Inheritance Model classes.

-pkgPrefix type prefix
Wherever type is encountered at file scope, prefix the generated Java package name with prefix for all files generated for that type. The type is the simple name of either a top-level module, or an IDL type defined outside of any module.

-pkgTranslate type package
Whenever the module name type is encountered in an identifier, replace it in the identifier with package for all files in the generated Java package. Note that pkgPrefix changes are made first. type is the simple name of either a top-level module, or an IDL type defined outside of any module, and must match the full package name exactly.

If more than one translation matches an identifier, the longest match is chosen. For example, if the arguments include:

  -pkgTranslate foo bar -pkgTranslate foo.baz buzz.fizz

The following translations would occur:

foo          =>	bar      =>
foo.baz      =>	buzz.fizz  =>

The following package names cannot be translated:

  • org
  • org.omg or any subpackages of org.omg

Any attempt to translate these packages will result in uncompilable code, and the use of these packages as the first argument after -pkgTranslate will be treated as an error.

-skeletonName xxx%yyy
Use xxx%yyy as the pattern for naming the skeleton. The defaults are:
  • %POA for the POA base class (-fserver or -fall)
  • _%ImplBase for the oldImplBase class (-oldImplBase and (-fserver or -fall))

-td dir
Use dir for the output directory instead of the current directory.

-tieName xxx%yyy
Name the tie according to the pattern. The defaults are:
  • %POATie for the POA tie base class (-fserverTie or -fallTie)
  • %_Tie for the oldImplBase tie class (-oldImplBase and (-fserverTie or -fallTie))

-nowarn, -verbose
Verbose mode.

Display version information and terminate.
See the Description section for more option information.


Known Problems:

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