It is very important to realized that the HDF Java API is an interface to the regular HDF library. A Java program access the HDF files through the same HDF library code as a C program.
2) Can I read any given HDF file with the JHV?
The Java HDF products are generally compatible with all HDF files produced
by the NCSA HDF library.
Due to memory limits in the implementation of Java Virtual Machines, it may not be possible to view some large images and datasets at full resolution.
The Java HDF Viewer can display the objects and metadata from
most HDF files.
It can show the data from two and three dimensional datasets
and tables.
Higher dimensional data cannot be visualized.
3) Can I read HDF-EOS files with the JHV?
HDF-EOS is a profile that runs on top of the standard HDF library.
HDF-EOS provides standard metadata for EOS data, and several object
types not supported by HDF (grid, swath, and point). HDF-EOS
data objects and metadata are stored as combinations of
standard HDF objects.
The HDF Java products can access HDF-EOS files, and will show
all their contents.
However, the NCSA HDF Java products do not "understand" HDF-EOS
metadata or objects.
Consequently, the meaning of the contents of an HDF-EOS file might
be difficult to interpret using the NCSA Java products.
4) How do I use HDF with Java?
Java applications access HDF by using the package
'ncsa.hdf.hdflib',
which defines Java native
methods for most HDF library entry points. In general,
the Java program can do exactly the same operations as
a C program.
See the
Java HDF Interface
documentation.
6) Can I use the Java HDF Viewer with a Web browser?
The JHV uses the HDF library (i.e., the `native code' library)
to access the HDF files. Most Web browsers do not allow network
loaded applets to access disk files or native libraries. For this
reason, the current release of the JHV cannot be used as an applet.
Future releases may provide network loadable applets for accessing
HDF files.
7) Is there (will there be) a Java implmentation of the HDF library?
There are no current plans to re-write the HDF 4.1 in Java. This
would be a very large effort, which is not feasible at this time.
8) Can I save/edit/create HDF files with the JHV browser?
The Java HDF Viewer is a tool intended for browsing and visualizing
HDF files. The current release has no capability to write or modify
HDF files. Various editing features may be supported in the future.
9) What is the latest official release of HDF for Java, and what
platforms does it support ?
The Java HDF interface is part of
HDF version 4.1 Release 2.
The Java HDF interface is only supported on platforms which
support Java JDK 1.1.1 or above.
Platforms Supported for Java:
Platform(OS)
------------
Sun4(Solaris 2.5)
SGI-Indy(IRIX5.3)
IBM PC - Intel Pentium
Solarisx86 (2.5)
Linux(elf) 2.0.27
Windows NT/95
The current release supports nearly all the entry points described in the HDF 4.1r2 Reference Manual. A few routines were both difficult to implement and irrelevant to Java programs, and so were omitted.
There are many new features. See the
Release Notes.
11) Where can I get the HDF Java source code and information
relevant to Java and HDF?
The Java HDF source code is available as part of the HDF library
source.
For information, take a look at the HDF home page:
http://hdf.ncsa.uiuc.edu/
You can download the source code (free of charge) from the NCSA anonymous
ftp server or from the HDF anonymous ftp server (a mirror site of the NCSA
ftp server):
NCSA ftp server: ftp.ncsa.uiuc.edu
HDF ftp server: hdf.ncsa.uiuc.edu (141.142.21.14)
On the NCSA ftp server, the files are located in:
HDF/On the HDF ftp server, the files are located in:
pub/dist/HDF/
Information about the HDF Java products is available at:
All of the HDF documentation, old and new, is available on the NCSA ftp server (ftp.ncsa.uiuc.edu) in the directory:
/HDF/Documentation/
If running HDF 4.1r1, following is the documentation which
will be of use to you:
HDF User's Guide v4.1r1
Full coverage of all HDF routines and command-line utilities;
includes many examples. This is available in Postscript,
Framemaker MIF, and PDF formats from the NCSA ftp server
(ftp.ncsa.uiuc.edu) in the directory:
/HDF/Documentation/HDF4.1r1/Users_Guide/
ASCII versions of the examples from the User's Guide can be
found in:
/HDF/Documentation/HDF4.1r1/Users_Guide/Examples_ASCII/
HDF Reference Manual V4.1r1
An alphabetical listing of all HDF routines and command-line
utilities. An html version is available from the HDF home page
under "Information about HDF" (http://hdf.ncsa.uiuc.edu/doc.html).
It is available in Postscript, Framemaker MIF, PDF, and HTML formats
from the NCSA ftp server (ftp.ncsa.uiuc.edu) in the directories:
/HDF/Documentation/HDF4.1r1/Ref_Manual/ (ps, mif, pdf)
/HDF/Documentation/HDF4.1r1/Ref_Manual/html/ (html)
HDF Specifications and Developer's Guide v3.2
Designed for those who need detailed information about HDF, such as HDF
application program interface developers. It describes the basic
structure, components, and software layers of HDF; it specifies
supported HDF tags and discusses the portability of HDF. It is
available from the NCSA ftp server (ftp.ncsa.uiuc.edu) in the
directory:
/HDF/Documentation/HDF.Specs/HDFSpecs.old.postscript/
A relatively newer Macintosh version is also available:
/HDF/Documentation/HDF.Specs/HDFSpecs_DG.msw.sit.hqx
To configure the distribution, cd to the 'java-hdf' and type:
./configure
To compile the HDF library interface and JHV utility, type:
make
To find out the available make targets, type:
make help
To install the HDF Java classes, support libraries, and JHV utility,
type:
make install
To install the 'javadoc' man pages for the HDF Java classes, type:
make install-javadocs
See the README and the INSTALL files in the java-hdf directory.
14) How do I compile Java application programs that call
HDF functions?
A Java application uses the HDF library by importing the Java
package
'ncsa.hdf.hdflib.'.
The Java classes must be in a directory in CLASSPATH, and
the HDF Java library must be in the LD_LIBRARY_PATH.
For more information, see the
Java HDF Inteface
page.
15) Is there a Habanerof version of the JHV?
No.
16) Which NCSA Java tools can I use to view HDF objects?
The HDF Java distribution includes the NCSA Java-based HDF Viewer (JHV).
The JHV is compiled and installed as part of the Java HDF package.
The JHV is invoked by the script provided in the Java HDF distribution,
'bin/jhv', which is configured and installed as part of the build.
17) Is there any commercial or public domain Java software
that accesses HDF files?
Find out
It is not known for sure what Java tools use HDF.
18) What versions of HDF are supported for Java?
The Java HDF interface is built using HDF 4.1r1. It is compatible
with everything that HDF 4.1 is compatible with.
19) What versions of Java can I use?
The current release of the JHV requires Java JDK 1.1 or above.
20) Is there a mailing list for discussions and
questions about HDF and Java?
"hdf-java@ncsa.uiuc.edu" is a mailing list for HDF and its users to share
ideas and information about the HDF and Java.
If you wish to be added to or removed from the "hdf-java" mailing list,
send an e-mail message to ncsalist@ncsa.uiuc.edu with the appropriate
command in the body of the message. Commands in the subject line are
NOT processed. Valid commands include:
subscribe hdf-java [<address>]
unsubscribe hdf-java [<address>]
help
We recommend that you send the "help" command to retrieve the full list
of available commands.
If you have any problem subscribing/unsubscribing, feel free to contact
hdfhelp@ncsa.uiuc.edu. To unsubscribe, the e-mail address you
send must match exactly the e-mail address with which you subscribed.
(If you do not specify an address, the address from which you send the
e-mail must match your subscription address.)
18) How do I make a bug report?
All bug reports, comments, suggestions and questions should go to
hdfhelp@ncsa.uiuc.edu.
Attached below is a bug report template. It is very helpful to us as
far as locating and fixing the bug if all the information inquired
in the template is supplied by the reporter.
------------------ Template for bug report ------------------------
To: hdfhelp@ncsa.uiuc.edu
Subject: [area]: [synopsis] [replace with actual AREA and SYNOPSIS]
VERSION:
HDF4.1 release 1 (Java)
USER:
[Name, phone number and address of person reporting the bug.
(email address if possible)]
AREA:
[Area of the HDF source tree affected, e.g., src, util, test,
toplevel. If there are bugs in more than one AREA, please use
a separate bug report for each AREA. ]
SYNOPSIS:
[Brief description of the problem and where it is located]
MACHINE / OPERATING SYSTEM:
[e.g. Sparc/SunOS 4.1.3, HP9000/730-HPUX9.03...]
COMPILER:
[e.g. native cc, native ANSI cc, gcc 2.63, MPW, ...]
DESCRIPTION:
[Detailed description of problem. ]
REPEAT BUG BY:
[What you did to get the error; include test program or session
transcript if at all possible. If you include a program, make
sure it depends only on libraries in the HDF distribution, not
on any vendor or third-party libraries. Please be specific;
if we can't reproduce it, we can't fix it. Tell us exactly what
we should see when the program is run. ]
SAMPLE FIX:
[If available, please send context diffs (diff -c)]
[PLEASE make your Subject(SYNOPSIS): line as descriptive as possible.]
[Remove all the explanatory text in brackets before mailing.]
[Send to hdfhelp@ncsa.uiuc.edu or to:
NCSA
HDF group
605 E. Springfield Ave.
Champaign, IL 61820 ]
------------------ End of Bug Report Template ----------------------