Alexander Schunk's Blog

October 2007 Archives

Java on Mac: what the hec?

Compile once, dont run anywhere?

So whats this controversy or non-contreversy thing with Java all about? And what about compile once run anwyher? And isnt its SUNs Job to get things work on the OS plattform they support and not Apple?

Ok. To make me understand: at the beginning of this year i joined the OpenJDK discussion lists and i was told the Vista is not one of SUns favorite OSes for Java 7. Now everyone seems to acknowledge that Windows Vista is - despite the problems with Vista Microsoft has - the very one plattform and MAC is not. So whats up with Java 7? Is it going to run on MAC, Linux, Vista or only Vista and Linux?.

Java Closures: programming in closures?

Why closures?

If i get things right the closures project aims to pack multiple statements into one logical program unit. For instance the following line would be a logical programming unit:

{
 int x = 3;
 int y = 4;
 int s => x + y;
}

So in this case you have two ints that you add together and this code works as one logic programming unit. I dont see between this code and this code:

int x = 4;
int y = 3;
int sum = x+y;
System.out.println("x + y " + sum);

And - if someone wants to use a more procedureal way - he can put this into a method as follows:

public int add(int x, int y){
return x+y;
}

However the closures project also offers a closures syntax for methods. Does this mean Java is making a shift to a more procedural programming philosphy? May be i am too far on the surface but i dont see the big benefit of closures right now but may be there is one i did not capture yet.

OpenJDK: Repositories overview

Master and Slave

Reading Kellys Blog it seems like the main target group of developers for OpenJDK is moving from pure Desktop applications to Webservice related applications.

The Mercurial repositories of OpenJDK include jws, jdk, java2d, ti, and some other interesting APIs. However some APIs - mainly extended APIs - are not listed in the Master and Slave repository chart.

I assume these APIs will be included into OpenJDK to a later time or may be added using Modules. Anyway if this is the core of OpenJDK or Java 7 it looks like Java will shrink in its core features and is open for new extension API development. However this is just my personal interpretation.

In this case external APIs from third party developers will have to comply and meet the software development guideliness as imposed by the OpenJDK community charter and legal documents.

j2se is obsolete.. use jdk instead

j2se is obsolete: Really?

When reading Kelly Oheirs Glossary for OpenJDK i noticed far below an entry running:

j2se

".....: this is an old word. Use jdk instead. Never let marketing control your products versioning number"

Is SUN really going to change its marketing driven Versioning system of Java SDKs and use a new more reasonably and straightforward system? Will we only have jdk7, jdk8, jdk9 in the future?

That would help many people working with Java releases. For instance if you are applying for a job you just need to write "knows jdk7 and jdk8 with J2EE5.".

What an achievement. Anyone would understand it. Compare this with the following statement no one would understand on first sight:

"Have excellent Java programming skills, know OpenJDK6, OpenJDK7, J2EE 5.5 and J2SE.".

Having a solid and straight forward versioning system will really help people to talk over the same things and technologies rather than trying to explain what they mean.

Search and Sort with Java

Search and Sort API for Java

While working on some simple applications i realized that there is no standard seaerch and sort API for Java but a lot of books covering Algorithms in Java i.g. "Sedgewicks Algorithm in Java".

However it would be easy to implement common algorithms for basic purposes in Java for instance things like linear search binary search or sorting algorithms like bubble sort, quick sort etc.

While most applications require a special implementation of certain standard algorithms a standard API for algorithms in Java might help in certain common tasks.

Another field of algorithms is hashing and algorithms for Graphs. Most common algorithms on Graphs are documented well and lots of implementations are around there. Again a standard API for Graphs algorithms might help for certain common tasks.

Possible implementation

A possible way to implement search and sort functionlity would be to use an interface like Comparable and Comparator for searching:

public interface Sortable{
  public int sort(Object[] items);
}

Another way is to use concrete classes:

public class BasicSearch{

 public Object linearSearch(Object[] item, Object key){

  }
}

There are various ways to implement such an API but i think having concrete classes or interfaces is a good way to do it.

So its a question to the community if there is a need for a standard API for searching, sorting and may be Graphs.

Java 6: Update N Nice but

Java: Update N

The Consumer JRE or Update N for Java 6 is a good one solving some bottlenecks of previous Java versions.

Except Quickstart and Nimbus all items of the new Update worked pretty well on my Win XP Notebook.

I was trying some Java apps i have written but i did not see a remarkable launch improvement instead they were running as usual.

The Deployment Toolkit is a nice Add-On for the Browser telling me that i am using Java 1.7.0 on my Windows.

I have no hard figures for Quickstart on Win XP but i feel my Swing apps already run smooth and have appropriate start up times.

Concerning Nimbus i would love to see it working on Win XP so i hope it will be stable in the near future.

Great work.

LinAlg API: Stable release available for Download

LinAlg Stable release

A first stable release of LinAlg API is available. You can download it from the LinAlg API project homepage at linalg.dev.java.net.

Demos

With this first stable release i have provided some demo apps. These demo apps are:

• Angle Converter
• Complex Calculator
• PASCAL

The angle converter simply converters angles from degree to radians. One drawback is then when converting back from radians to degree you have to specify the angle with all digits otherwise the result is wrong.

Complex Calculator supports the basic complex operations like +, -, *, /, abs(), tan() for Complex Numbers.

PASCAL supports basic Vector 3D operations like +, - ,* , /, abs() etc.

You can download the demo apps from the project homepage in the LinAlgDemos folder. For screenshots see the Demos folder.

Bug Reports

I would be happy to receive any user feedback or bug reports of LinAlg API so feel free to post them.

This work is licensed under a Creative Commons License.