Re: [Classpath] Question about Boolean

[C. Scott Ananian]

On Thu, 19 Jul 2001, C. Scott Ananian wrote:

> On 19 Jul 2001, Tom Tromey wrote:
> 
> > -    public static final Class TYPE = 
> > VMClassLoader.getPrimitiveClass("boolean");
> > +    public static final Class TYPE = boolean.class;
> 
> With jikes, at least, this actually compiles to:
>   public static final Class TYPE = Boolean.TYPE;
> which is probably not what you meant.

I just verified that javac compiles this in the same way.

Foo.java:
 public class foo {
    Class field = boolean.class;
 }
Compiling:
% java -version
java version "1.3.0"
% javac -d . -g foo.java

Disassembling:
% javap -c foo
Compiled from foo.java
public class foo extends java.lang.Object {
    java.lang.Class field;
    public foo();
}

Method foo()
   0 aload_0
   1 invokespecial #1 <Method java.lang.Object()>
   4 aload_0
   5 getstatic #2 <Field java.lang.Class TYPE>
   8 putfield #3 <Field java.lang.Class field>
  11 return
---------
It's hard to tell that pc 5 is in fact a load from Boolean.TYPE (with
type java.lang.Class); my harpoon compiler loading this bytecode is more
clear:

% java harpoon.Main.Main foo
Codeview "bytecode" for public foo():
  #0/foo.java:1 - aload_0 lv_0
  #1/foo.java:1 - invokespecial public java.lang.Object()
  #2/foo.java:2 - aload_0 lv_0
  #3/foo.java:2 - getstatic public static final java.lang.Class 
java.lang.Boolean.TYPE
  #4/foo.java:2 - putfield java.lang.Class foo.field
  #5/foo.java:1 - return

Hope this makes clear why the Classpath code is written as it is.
 --s

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