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+ + + +

Java has issues

+ Posted on 2011/01/03 by lts +

This was originally posted to Facebook by me at 2010-09-02 23:19. It was edited by me there 2010-07-03.

Java is an alright language. There are a lot of things it does right, but there
+are a few things it doesn’t.

Distinction between classes and packages. I should be able to create
+ sub-classes the same way as I add classes to a package; a package should
+ just be an empty class.
Too many primitives. I should be able to (re-)construct more of the
+ language.
No preprocessor/inlines. OO isn’t an excuse for this, make me do it at the
+ class level (or rather, source file, not supporting `#include’ is fine). I
+ should at least be able to add `#define int8=byte’ like in C. This
+ wouldn’t be as much of an issue if all these things weren’t primitives; I
+ could just do “public class int8 extends byte”. (yes, I could extend the
+ `Byte’ class, but it wouldn’t come with all the syntactic sugar primitives
+ get.)
Numbers: names. Yes the names used are long-standing convention in CS.
+ These include some of the worst short-sighted mistakes in all of
+ hackerdom… because they stuck. Yet, most reasonable languages can still
+ support them, and sane equivalents.
+
- byte -> int8
- short -> int16
- int -> int32
- long -> int64
- float -> float32
- double -> float64
+
This would easily be fixed if they weren’t all primitives (point 2), or if
+ I had a preprocessor (point 3).
Numbers: unsigned. How about unsigned integers (uint16)? This would be
+ easy to implement, if everything weren’t a damn primitive.
Give me an actual `struct’, like in C. I’m not asking for full manual
+ memory management, just the ability to organize a chunk of it; you can
+ still manage it for me. It would make serialization hellofalot
+ easier.
It’s inconsistent about whether it uses the system encoding or it’s
+ internal encoding. The String object just became worthless to anyone
+ wanting to do any amount of I18N.
It’s internal encoding is junk. It maps UTF-16 symbols onto the `char’
+ primitive, which is 16 bits.
+
1. UTF-16 is junk, use UTF-8
2. With any UTF encoding you must allow for a dynamic bit-length, for
  + UTF-16 it’s 16-32 bits, UTF-8 is 8-32 bits
+
I understand how/why it arrived at the solution it uses; at the time Java
+ was designed, it was using UCS-2, which is a 16-bit encoding, and was
+ superseded by UTF-16 in 1996 with Unicode 2.0. However, this is one of
+ those things where you specify a new JVM version, and switch to UTF-8. You
+ can even leave a legacy mode in the JVM that still uses UCS-2.
Octal prefix: `0′ is used as the prefix to specify an octal literal. Any
+ third-grader can tell you why using a 0 as a prefix to a number is a bad
+ idea; the number might just have padded zeros. Let’s look at the prefix
+ used for hexadecimal: `0x’. This is great:
+
1. It starts with a numeric character, which means that it must be a
  + literal. If it started with an alphabetic character, it might be a
  + variable name.
2. The second character is a alphabetic character that is not used in
  + any number system that is used in computer science. This allows it
  + to serve a a unique identifier.
+
Given these reasons, let’s think of a new prefix for octal… how about
+ `0o’. That took literally less than 10 seconds for me to realize why `0′
+ sucked, and to think of a better one.*

All-in-all, its still better than C++

* although, writing this gave me an even
+better idea, but it would break `0x<value>’ for hex, which is incredibly
+common among many languages:
+`<base-in-decimal>x<value>’
+so octal would be `8x<value>’
+and hex would be `16x<value>’
+It would be incredibly understandable, and, depending on implementation allow
+simple arbitrary-base literals.

+ +

+ This entry was posted in Computers. Bookmark the permalink. + +

+ + + + + +

Leave a Reply Cancel reply

+ +

+ + + + + + diff --git a/web/lukeshu.ath.cx/1/wordpress/2011/01/java-has-issues/index.html b/web/lukeshu.ath.cx/1/wordpress/2011/01/java-has-issues/index.html new file mode 100644 index 0000000..99e751c --- /dev/null +++ b/web/lukeshu.ath.cx/1/wordpress/2011/01/java-has-issues/index.html @@ -0,0 +1,266 @@ + + + + + Java has issues | ltsBlog + + + + + + + + + + + + + + + + + + + + + + +

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+ + +

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+ +

+ + + + + + + + +

+ + + +

Java has issues

+ Posted on 2011/01/03 by lts +

This was originally posted to Facebook by me at 2010-09-02 23:19. It was edited by me there 2010-07-03.

Java is an alright language. There are a lot of things it does right, but there
+are a few things it doesn’t.

Distinction between classes and packages. I should be able to create
+ sub-classes the same way as I add classes to a package; a package should
+ just be an empty class.
Too many primitives. I should be able to (re-)construct more of the
+ language.
No preprocessor/inlines. OO isn’t an excuse for this, make me do it at the
+ class level (or rather, source file, not supporting `#include’ is fine). I
+ should at least be able to add `#define int8=byte’ like in C. This
+ wouldn’t be as much of an issue if all these things weren’t primitives; I
+ could just do “public class int8 extends byte”. (yes, I could extend the
+ `Byte’ class, but it wouldn’t come with all the syntactic sugar primitives
+ get.)
Numbers: names. Yes the names used are long-standing convention in CS.
+ These include some of the worst short-sighted mistakes in all of
+ hackerdom… because they stuck. Yet, most reasonable languages can still
+ support them, and sane equivalents.
+
- byte -> int8
- short -> int16
- int -> int32
- long -> int64
- float -> float32
- double -> float64
+
This would easily be fixed if they weren’t all primitives (point 2), or if
+ I had a preprocessor (point 3).
Numbers: unsigned. How about unsigned integers (uint16)? This would be
+ easy to implement, if everything weren’t a damn primitive.
Give me an actual `struct’, like in C. I’m not asking for full manual
+ memory management, just the ability to organize a chunk of it; you can
+ still manage it for me. It would make serialization hellofalot
+ easier.
It’s inconsistent about whether it uses the system encoding or it’s
+ internal encoding. The String object just became worthless to anyone
+ wanting to do any amount of I18N.
It’s internal encoding is junk. It maps UTF-16 symbols onto the `char’
+ primitive, which is 16 bits.
+
1. UTF-16 is junk, use UTF-8
2. With any UTF encoding you must allow for a dynamic bit-length, for
  + UTF-16 it’s 16-32 bits, UTF-8 is 8-32 bits
+
I understand how/why it arrived at the solution it uses; at the time Java
+ was designed, it was using UCS-2, which is a 16-bit encoding, and was
+ superseded by UTF-16 in 1996 with Unicode 2.0. However, this is one of
+ those things where you specify a new JVM version, and switch to UTF-8. You
+ can even leave a legacy mode in the JVM that still uses UCS-2.
Octal prefix: `0′ is used as the prefix to specify an octal literal. Any
+ third-grader can tell you why using a 0 as a prefix to a number is a bad
+ idea; the number might just have padded zeros. Let’s look at the prefix
+ used for hexadecimal: `0x’. This is great:
+
1. It starts with a numeric character, which means that it must be a
  + literal. If it started with an alphabetic character, it might be a
  + variable name.
2. The second character is a alphabetic character that is not used in
  + any number system that is used in computer science. This allows it
  + to serve a a unique identifier.
+
Given these reasons, let’s think of a new prefix for octal… how about
+ `0o’. That took literally less than 10 seconds for me to realize why `0′
+ sucked, and to think of a better one.*

All-in-all, its still better than C++

+ +

+ This entry was posted in Computers. Bookmark the permalink. + +

+ + + + + +

Leave a Reply Cancel reply

+ +

+ + + + + + diff --git a/web/lukeshu.ath.cx/1/wordpress/2011/01/pointers-in-java/index.chtml b/web/lukeshu.ath.cx/1/wordpress/2011/01/pointers-in-java/index.chtml new file mode 100644 index 0000000..860edd2 --- /dev/null +++ b/web/lukeshu.ath.cx/1/wordpress/2011/01/pointers-in-java/index.chtml @@ -0,0 +1,328 @@ + +

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Pointers in Java

+ Posted on 2011/01/03 by lts +

This was originally posted to Facebook by me at 2010-08-02 23:20.

Note: For purposes of anyone interested in this, pointers in Java are more commonly referred to as references, because everything in Java must have it’s own name (method vs. function). This makes operating the ~~Google~~ DuckDuckGo machine easier. I wish I had known that when I wrote this.

+In Java there are a few `primitive' datatypes, the rest of the datatypes are
+implemented as classes.  They are:
+
+byte
+short
+int
+long
+float
+double
+char
+<pointer>
+
+Normally, when declaring a primitive, you write the type of the primitive as
+the variable type.  However, the reason I wrote pointer in brackets is that you
+DON'T write pointer when declaring a variable storing a pointer.
+
+For example, when I write
+java.util.Stack stack = new java.util.Stack();
+The variable stack does NOT store an object. It stores a /pointer/ to an object.
+A pointer stores the memory address where a object is stored.
+
+ALL VARIABLES STORE PRIMITIVES, IT IS IMPOSSIBLE TO STORE AN OBJECT.
+For this reason, it is possible for the JVM to manage memory for you; it keeps
+track of the pointers, and once there are no more pointers pointing to a
+particular object, it can be deleted.
+
+Why does this matter?  Well, consider that `String' is a class
+(`java.lang.String'), not a primitive.  Consider the following code:
+
+String str1 = "foo";
+String str2 = "foo";
+return (str1 == str2);
+
+If String were a primitive, it would return true; but it returns false.
+Strings are a little complex because they contain syntactic sugar.  Let's do
+the same example with an integer instead:
+
+Integer int1 = new Integer(5);
+Integer int2 = new Integer(5);
+return (int1 == int2);
+
+The `java.lang.Integer' class is a class wrapper around the `int' primitive.
+The `new' operator creates a class, and returns a pointer to it.  The source
+code to the java.lang.Integer class contains the:
+    private int value;
+
+    public Integer(int val) {
+        value = val;
+    }
+
+So, the above example generates to objects belonging to the java.lang.Integer
+class.  Even though the .value's of the two objects are the same, they are
+separate objects.  Therefore, int1 and int2 store two separate memory locations.
+These two locations in the memory store the same data, but it is stored at both
+locations.
+
+The `==' operator takes two primitives, and compares their direct values.
+Since int1 and int2 store two different memory locations, `(int1 == int2)'
+evaluates to false.
+

Note: as pointed out by Ari Consul, everything following is false. The JVM does not copy the objects, it returns the pointer directly (no magic, as I’d suggested). The JVM will free() the object when there are no more pointers to it, via basic reference-counting

+About copying objects:  when returning a private pointer, the JVM makes a copy
+of the object that the pointer points to, and returns a pointer to the new
+object, NOT the original pointer.
+
+For example if I declare the method:
+
+public static Integer getInt() {
+    Integer val = new Integer(5);
+    return val;
+}
+
+It does NOT actually return `val'; it returns a new pointer to a copy of the
+object that val pointed to.
+

+ +

+ This entry was posted in Computers. Bookmark the permalink. + +

+ + + + + +

+ +

2 Responses to Pointers in Java

+ +

+
+
+ + Ari Consul says: +
+ +
+ 2011/06/22 at 05:14 +
+
+
Nice blog, keep discovering and posting!
+
The last part is incorrect. getInt() (a bad name BTW: newIntFive() or intFiveFactory() would be a better description) creates a new Integer object, a reference to the Integer object and assigns the object reference to val. getInt() then returns a copy of the object reference. There is no implicit object copying here.
+
Some relevant URLs:
+http://oopweb.com/Java/Documents/ThinkingInJava/Volume/TIJ319.htm#Index2146
+http://javadude.com/articles/passbyvalue.htm
+http://java.sun.com/docs/books/jls/third_edition/html/statements.html#6767
+
+
+ Reply +
+
+ +
- +
  +
  + + lts says: +
  + +
  + 2011/06/29 at 05:05 +
  +
  +
  Thank you!
  +
  I know that now, but at the time I’d written it, I had been using Java for ~~less than 6 months~~a very short time. My previous statement was based on a flawed understanding of how Java did garbage collection.
  +
  Of course, the code example wasn’t meant to do anything, just be an example of allocing an object and returning a pointer.
  +
  BTW, if you don’t mind me asking, what lead you here?
  +
  +
  + Reply +
  +
  + +
+

Leave a Reply Cancel reply

+ +

+ + + + + + diff --git a/web/lukeshu.ath.cx/1/wordpress/2011/01/pointers-in-java/index.html b/web/lukeshu.ath.cx/1/wordpress/2011/01/pointers-in-java/index.html new file mode 100644 index 0000000..6e78d68 --- /dev/null +++ b/web/lukeshu.ath.cx/1/wordpress/2011/01/pointers-in-java/index.html @@ -0,0 +1,325 @@ + + + + + Pointers in Java | ltsBlog + + + + + + + + + + + + + + + + + + + + + + +

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+ + +

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+ +

+ + + +

+
+ Search ltsBlog: + + +
+
+
Me on identi.ca
- "The darkest places in hell are reserved for those who maintain their neutrality in times of moral crisis." - Dante Alighieri 2011/12/13
- Someone egged a bunch of cars in our neighborhood. 2011/12/03
- !git. is. such. win. 2011/11/27
- My favorite sites could get shut down by 1st censorship system for the internet. Must stop it: 11/16 http://ur1.ca/5qyod 2011/11/16
Recent Posts
+
Recent Comments
- Fixing “Wrong type argument: characterp, return” in !Emacs | ltsBlog on [Emacs] autopair problems when using term-mode
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- lts on Pointers in Java
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Archives
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+
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+
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+
- + + + + + +
+

+ + + + +

+ + + +

Pointers in Java

+ Posted on 2011/01/03 by lts +

This was originally posted to Facebook by me at 2010-08-02 23:20.

+In Java there are a few `primitive' datatypes, the rest of the datatypes are
+implemented as classes.  They are:
+
+byte
+short
+int
+long
+float
+double
+char
+<pointer>
+
+Normally, when declaring a primitive, you write the type of the primitive as
+the variable type.  However, the reason I wrote pointer in brackets is that you
+DON'T write pointer when declaring a variable storing a pointer.
+
+For example, when I write
+java.util.Stack stack = new java.util.Stack();
+The variable stack does NOT store an object. It stores a /pointer/ to an object.
+A pointer stores the memory address where a object is stored.
+
+ALL VARIABLES STORE PRIMITIVES, IT IS IMPOSSIBLE TO STORE AN OBJECT.
+For this reason, it is possible for the JVM to manage memory for you; it keeps
+track of the pointers, and once there are no more pointers pointing to a
+particular object, it can be deleted.
+
+Why does this matter?  Well, consider that `String' is a class
+(`java.lang.String'), not a primitive.  Consider the following code:
+
+String str1 = "foo";
+String str2 = "foo";
+return (str1 == str2);
+
+If String were a primitive, it would return true; but it returns false.
+Strings are a little complex because they contain syntactic sugar.  Let's do
+the same example with an integer instead:
+
+Integer int1 = new Integer(5);
+Integer int2 = new Integer(5);
+return (int1 == int2);
+
+The `java.lang.Integer' class is a class wrapper around the `int' primitive.
+The `new' operator creates a class, and returns a pointer to it.  The source
+code to the java.lang.Integer class contains the:
+    private int value;
+
+    public Integer(int val) {
+        value = val;
+    }
+
+So, the above example generates to objects belonging to the java.lang.Integer
+class.  Even though the .value's of the two objects are the same, they are
+separate objects.  Therefore, int1 and int2 store two separate memory locations.
+These two locations in the memory store the same data, but it is stored at both
+locations.
+
+The `==' operator takes two primitives, and compares their direct values.
+Since int1 and int2 store two different memory locations, `(int1 == int2)'
+evaluates to false.
+

+About copying objects:  when returning a private pointer, the JVM makes a copy
+of the object that the pointer points to, and returns a pointer to the new
+object, NOT the original pointer.
+
+For example if I declare the method:
+
+public static Integer getInt() {
+    Integer val = new Integer(5);
+    return val;
+}
+
+It does NOT actually return `val'; it returns a new pointer to a copy of the
+object that val pointed to.
+

+ +

+ This entry was posted in Computers. Bookmark the permalink. + +

+ + + + + +

+ +

2 Responses to Pointers in Java

+ +

+
+
+ + Ari Consul says: +
+ +
+ 2011/06/22 at 05:14 +
+
+
Nice blog, keep discovering and posting!
+
The last part is incorrect. getInt() (a bad name BTW: newIntFive() or intFiveFactory() would be a better description) creates a new Integer object, a reference to the Integer object and assigns the object reference to val. getInt() then returns a copy of the object reference. There is no implicit object copying here.
+
Some relevant URLs:
+http://oopweb.com/Java/Documents/ThinkingInJava/Volume/TIJ319.htm#Index2146
+http://javadude.com/articles/passbyvalue.htm
+http://java.sun.com/docs/books/jls/third_edition/html/statements.html#6767
+
+
+ Reply +
+
+ +
- +
  +
  + + lts says: +
  + +
  + 2011/06/29 at 05:05 +
  +
  +
  Thank you!
  +
  I know that now, but at the time I’d written it, I had been using Java for ~~less than 6 months~~a very short time. My previous statement was based on a flawed understanding of how Java did garbage collection.
  +
  Of course, the code example wasn’t meant to do anything, just be an example of allocing an object and returning a pointer.
  +
  BTW, if you don’t mind me asking, what lead you here?
  +
  +
  + Reply +
  +
  + +
+

Leave a Reply Cancel reply

+ +

+ + + + + + -- cgit v1.2.3-2-g168b

ltsBlog

Monthly Archives: January 2011

Pointers in Java

Java has issues

ltsBlog

Monthly Archives: January 2011

Pointers in Java

Java has issues

ltsBlog

Java has issues

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Java has issues

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Pointers in Java

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