John D. Mitchell's Blog

J2SE v1.5 'Tiger' beta 1 release

Sun has released J2SE v1.5 beta 1. Go wild!

Comments

• Eclipse and JSK 1.5
  JDK 1.5 can be tested within Eclipse with this early access plugin : http://www.genady.net/forum/viewtopic.php?t=31&sid=f9aebf4a34651debb44e03b72bed1c8e
  

  Posted by: dgageot on February 05, 2004 at 04:46 AM

• So far so good
  Just been looking at the demos. The start up time is 1 sec on my 1Ghz WinXP with 512Mb, and about 2 secs on my work PC. Time to play around and see if I can break it. Also time to see if the code I wrote with the generics 2.2 pre-release will work.

  Posted by: wgauvin on February 05, 2004 at 06:58 AM

• Generics question
  Ok, I've been looking at the generics and I just can't quite wrap my mind around something. I'm looking at the Collections.java implementation, which has the following line:

  private interface SelfComparable extends Comparable {}

  Ok, so we want a comparable interfact that only can compare things of SelfComparable. Is that right?

  But...NOTHING in Collections implements it, yet some methods (min/max) expect things of type comparable. I'm completely baffled how, if nothing implements SelfComparable, how any SelfComparable objects get created. It's a private interface, so other classes aren't implementing it, and there's no reflection in Comparable that creates one.

  Anyone?

  Posted by: ckessel on February 09, 2004 at 08:37 AM

• Generics question
  Grr, we desperately need an "edit" ability. I meant to say some methods (min/max) expect things of type *SelfComparable*.

  Posted by: ckessel on February 09, 2004 at 08:39 AM

• Generics
  I tried JDK1.5beta and confused about Generics.

  I thought this might work, but didn't.

  public static > void sort(T[] a)

  this worked...

  public static > void sort(T[] a)

  Why is there a such incompatibility with an usual class definition?

  By the way, I prefer Generics parameter to be placed next to the function's name. (like C++)

  public static void sort > (T[] a)

  Thank you.
  

  Posted by: whiterabbit on February 09, 2004 at 08:38 PM

• Generics
  Next one.

  This code cannot be compiled (with error message "you cannot use built-in array for generics type") even if the commented out "Integer" version works.

  I really love new Swing L&F "Ocean", and likes extended for-loop, but I think Generics might be too early for JDK1.5. It's very confusing. And once it's introduced, we cannot go back.

  import java.util.*;

  class Hoge> implements Comparable>
  {
  private T _value;

  public Hoge(T value)
  {
  _value = value;
  }

  public int compareTo(Hoge h)
  {
  return _value.compareTo(h._value);
  }

  public String toString()
  {
  return String.valueOf(_value);
  }
  }

  class MeApp
  {
  public static void main(String[] args)
  {

  Hoge[] a = new Hoge[] {
  new Hoge(4),
  new Hoge(1),
  new Hoge(3)
  };
  /*
  Integer[] a = new Integer[] {
  new Integer(4),
  new Integer(1),
  new Integer(3)
  };
  */
  Arrays.sort(a);

  for (Hoge x : a)
  {
  System.out.println(x);
  }
  /*
  for (Integer x : a)
  {
  System.out.println(x);
  }
  }
  */
  }

  Posted by: whiterabbit on February 09, 2004 at 09:12 PM

• Generics
  Sorry, I didn't read specification and forgot this is beta.

  I tried one experiment.

  I implemented sort algorithm in "Lib.java" and use it in "Client.java".

  # Lib.java
  public static > void sort(List list)

  After compiling them, change interface like this and compiled only "Lib.java".

  public static > void sort(List list)

  But still worked. I'm not familier with Java Generics yet, but this might be bettern than I thought...

  Posted by: whiterabbit on February 10, 2004 at 01:34 AM

• Generics Tutorial
  Check out Gilad's Generics Tutorial.
  

  Posted by: johnm on February 17, 2004 at 08:32 PM

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