JamVM 1.4.3 released on 21st May 2006
=====================================

A summary of changes since 1.4.2:

- Heap compaction implemented.  Previously on some programs the object
  allocation pattern could lead to a highly fragmented heap (lots of
  small holes).  This caused early heap expansion, and in some cases
  an OutOfMemory exception (a result of repeated heap expansion until
  heap fully expanded).

  JamVM now includes a mark/compact collector in addition to the
  mark/sweep GC.  This is normally ran after forced finalisation, and
  before heap expansion.  It removes fragmentation by sliding the objects
  to the bottom of the heap, closing the holes.

  Two new command line options can be used to control compaction :

    -Xnocompact : don't do compaction and just use the mark/sweep
                  collector.  This is equivalent to JamVM 1.4.2 behaviour.

    -Xcompactalways : do compaction on every garbage-collection.   In
                      some cases this may lead to less collections, but
                      the compactor is slower than the sweeper.

- The interned String table is now garbage-collected (JamVM uses its
  own interned String hashtable).

- Additional Java 1.5 support
    - New methods within VMClass implemented
        - isMemberClass, isLocalClass, isAnonymousClass,
          getEnclosingClass, getEnclosingMethod,
          getEnclosingConstructor, getClassSignature.

    - Generic signature support in reflection classes (Constructor, Method
      Field).
        - getTypeParameters, getSignature, getGenericExceptionTypes,
          getGenericParameterTypes, toGenericString, getGenericType,
          getGenericReturnType

    - Uncaught exceptions will now use the thread's uncaughtExceptionHandler
      (if available).

- Fix for Non-ASCII characters in class name parameter
    - affected methods Class.ForName, ClassLoader.defineClass

- Use getcwd() instead of PWD enviroment variable for user.dir
  property.  This fixes problems seen on some applications.

- Fix in VMClass.defineClass on 64-bit machines (protection domain
  parameter assumed to be 4 bytes).

- Minor interpreter optimisation in direct-mode with handler
  prefetch (reload of handler address in aload_0/getfield pair).

- Command line options -version and -showversion now prints a "Java
  compatible" version number.  This is to work with shell scripts which
  parse the output to get the Java version.

- Set the java.home property to the JAVA_HOME environment variable if set.

- Ported to Mac OS X on Intel.

- Runtime.availableProcessors implemented (Linux, Mac OS X and BSD
  systems).

- Updated to be compatible with Classpath 0.91.
    - Merged in changes to GNU Classpath's VM reference classes and
      JamVM's classes.

- Various compiler warnings.


JamVM 1.4.2 released on 22nd January 2006
=========================================

A summary of changes since 1.4.1:

- JamVM now supports class garbage-collection and unloading.  It is
  implemented according to the clarifications to the JLS.  This states
  that a class may be unloaded if and only if its class loader is
  unreachable.  As the loader is reachable while any classes defined
  by it are reachable, the class loader and all its classes will be
  collected together.

- Bug-fix for field name/type lookup and obfuscated code.  Previously
  a minor optimisation halted the search if a name was found with the
  wrong type (as a class cannot have two fields with the same name).
  However, this breaks obfuscated code which renames variables.  With 
  field resolution the optimisation is redundant, as fields are only
  looked up once.

- Added stub for VMClassLoader.defineClassWithTransformers.  This is
  a change in the VM interface in the generics branch of Classpath
  0.20.

- Various build changes :
    - fix errors/warnings on Open/Free BSD.  Part of this is a move
      to using config.h.

    - find Java compiler via path (try ecj, then jikes, gcj, javac).

- Fixed a minor garbage-collector bug.  Scan phase could SEGV if a GC
  occurred when a reference class was partially created.


JamVM 1.4.1 released on 28th November 2005
==========================================

A summary of changes since 1.4.0:

- As part of the GC optimisations in 1.4.0 some redundant checks were
  removed.  One of these was hiding a garbage-collector bug.  Classes
  that have not been linked should not be scanned, as their static
  fields have not been initialised.  The bug only manifested itself
  in certain applications, as the window between loading and linking
  is normally small.  Found with Tomcat, but also seen with Ant.
  
- Fix for an array overrun in VMAccessController.getStack (native
  method) on 64-bit machines.

- Support for FreeBSD.

- Support for OpenBSD (added in 1.3.3 but not previously mentioned).

- A couple of Mauve fixes relating to changing daemon status on threads
  that have died.


JamVM 1.4.0 released on 20th November 2005
==========================================

A summary of changes since 1.3.3:

- Support for Soft/Weak/Phantom References
    - As specified in the specification, Weak and Phantom References are
      cleared as soon as they become weakly or phantom reachable.  It is
      left up to the VM when Soft References (which are softly reachable)
      are cleared; only they must be cleared before throwing OutOfMemoryError.
      JamVM clears them as a last resort, when the heap is fully expanded,
      and insufficient memory can be reclaimed.

    - To support Soft/Weak/Phantom references a Reference Handler thread
      is now created on VM start-up.  This is additional to the Finaliser
      thread.

- Garbage Collector optimisations
    - Re-implementation of object reference scanning via reference offset
      lists.  Previously, references were scanned by finding references
      by following the class hierarchy.

    - As part of this the object layout has changed.

- Added Java language-level access checks (e.g. access to private/protected
  and package-private methods and fields).  This includes access via
  reflection.

- Fix for inheritance of inaccessible methods.

- Linux PowerPC build fix (this was quickly fixed in CVS).

- FFI fix.  The size of ffi-type-uint on 64-bit platforms has changed between
  libffi 2.00-beta and later versions.  This only affected AMD64, as this
  is the only platform that uses libffi.

- Fix for initiating loaders and array classes.

- Mauve tests.  Many extra VM-level Mauve tests now pass (35+).  These
  are mostly concerned with testing boundary-conditions in class-loading,
  Class.forName() and Thread.sleep().  Extra tests pass due to the
  implementation of Soft/Weak/PhantomReferences and access checks.

- Classpath-0.19 merge.
    - Merged in changes to GNU Classpath's VM reference classes and
      JamVM's classes.

- Support for kfreebsd and Linux-powerpc64.

- Many other code tidy-ups.


JamVM 1.3.3 released on 12th September 2005
===========================================

A summary of changes since 1.3.2:

- JamVM is now 64-bit "clean".

- As part of the changes above, JamVM has been ported to:

    - AMD64 under Linux:
        - JamVM should also work on Pentium 4 with EM64T technology.

    - PowerPC64 under Mac OS X:
        - to build a 64-bit executable CFLAGS must include the flag -arch
          ppc64.  If no option is given a 32-bit executable is built by
          default.

    - JamVM should also work on PowerPC64 under Linux, if the --enable-ffi
      flag is given to configure, but I have been unable to test.

- LibFFI is now supported.  Upto now, all ports required the native
  calling convention to be written "by hand" for each new architecture/
  platform.  Generic calling-convention code is now supported via libffi.
  Currently this is only used for AMD64/Linux, but can be enabled for
  all platforms using --enable-ffi.  The "hand-written" routines should
  be faster, and are used by default, but this will make porting to new
  architectures/platforms easier.

- Bug-fix enabling heaps larger than 2Gb to be specified on 32-bit
  architectures.  On 64-bit machines, heap sizes > 4Gb are now
  supported.

- Bug-fix for JNI return values smaller than 4 bytes (e.g.  byte, short,
  etc.) on big-endian machines.

- Under Mac OS X multiple DLL extensions will now be tried.  Classpath
  libraries end in .dylib, but native JNI libraries end in .jnilib.
  Both are now supported.

- Backwards compatibility workarounds for Classpath-0.17 removed.  JamVM
  will now only work with Classpath-0.18 and CVS (as of 12th September).


JamVM 1.3.2 released on 29th July 2005
======================================

JamVM 1.3.2 is a minor feature/bug-fix release.  A summary of changes since
1.3.1:

- Updated to be compatible with Classpath-0.17 and Classpath from
  CVS (as of 28th July).

- Shutdown hooks are now ran on VM termination, either normally, or via user
  interruption (i.e ctrl-C).

- Revised GC allocation failure policy
    - Using a simple heuristic the GC attempts to maintain at least 25% heap
      free.  If it fails the heap is expanded, regardless of whether the
      allocation request could be satisfied.  This reduces frequent garbage
      collection cycles when GC returns only a limited amount of memory.

- Revised Object finalization
    - during GC a thread could deadlock waiting for finalization.  This
      occurred when a finalizer (running in the finalizer thread) attempted
      to grab a lock the thread is holding.

    - a minor bug fix where finalized objects waiting for the finalizer to 
      be ran could keep alive other finalized objects (if it had the only
      reference to it).

    - a minor bug fix where objects waiting for finalization could be lost
      (i.e. finalize() method not called).  This only happened when >1000
      objects were outstanding.

    - VMRuntime.runFinalization() implemented.  This enables a thread to force
      finalization.

- In certain circumstances a class loader would be unmarked during GC,
  enabling it to be collected.  This resulted in a SEGV.

- JNI FindClass now uses the current class loader, not the first non-null on
  the stack.

- VMClass.getModifiers() now handles inner class attributes.

- Fix to enable build directory to be different to source directory (this was
  broken in 1.3.0).


JamVM 1.3.1 released on 12th June 2005
======================================

A summary of changes since 1.3.0:

- Re-worked thread suspension enable/disable code
    - implemented a fast enable/disable suspend mechanism for critical code
      sections, which is now used in hash table access and heap allocation :
        - much faster object allocation
        - much faster primitive array allocation
        - faster string interning

    - removed some minor potential (as yet unseen) race conditions

- Integrated all outstanding patches
    - generics branch patch, implementing VMClass.isEnum(), isAnnotation()
       and isSynthetic()

    - Boot library path patch (support for system property
      gnu.classpath.boot.library.path)

- Enabled different min/max heap values for each architecture
    - ARM values are back to the defaults for JamVM 1.2.5.  Default max heap
      of 128Mb is too large for typical embedded ARM systems.

- Fixed the new compiler warnings from gcc-4.0 (under Mac OS X) related
  to char/signed char usage.

- Fixed compiler error on gcc-4.0 under Mac OS X 10.4 (duplicate definitions
  of wait).

- Fixed rare, potential dead-lock in direct.c when preparing methods

- Fixed a bug in VMClassLoader.defineClass(), where offset or length is wrong.

- Fixed bug in DCONST_1 on mixed-endian ARM architectures (this bug was
  fixed in JamVM 1.2.2 but it crept back in, due to the new interpreter
   in JamVM 1.2.5).

- Improved thread dump (produced via SIGQUIT, or ctrl-\).

- Several other minor bug-fixes, and code tidy-ups.


JamVM 1.3.0 released on 31st March 2005
=======================================

A summary of changes since 1.2.5:

- Ported to Mac OS X/Darwin.  JamVM has been built and tested on Mac OS X
  10.3 (Panther), where it works "out-of-the-box".  It should also work
  on 10.2 (Jaguar) but you will need to install Fink (for dlopen
  compatibility).  Note only G3 and G4 machines have been tested.

    - As part of this, the source layout/build has been changed to more
      easily support different os/shared architectures

- The os.arch property now reports the machine architecture as follows:
    - arm  : ARM architecture (e.g. it previously reported armv5tel)
    - i386 : IA32 (i586, i686, etc.)
    - ppc  : PowerPC

- The ldc bytecode now handles "constant class" as specified in JSR 202
  (and introduced in Java 1.5)

- Command line options have been changed to be compatible with Sun Java.
  This particularly affects bootclasspath, which must now be given using
  the new syntax.  Two new options are implemented :
    - verbose:jni
    - showversion

- Default heap sizes have been increased (again) to better reflect desktop
  application heap usage :
    - minimum heap is now 2Mb
    - maximum heap is now 128Mb

- A race condition in class-loading has been fixed.  This fixes a SEGV
  with the latest postgreSQL JDBC driver.  It also fixes a SEGV when
  starting Eclipse on a P4 with hyper-threading enabled

- A race condition on VM initialisation has been fixed (helper threads
  starting when a GC cycle has already started in the main thread).


JamVM 1.2.5 released on 1st March 2005
======================================

- Substantially modified the interpreter to implement direct-dispatching.
  This considerably speeds-up dispatch, improving performance by 60% to
  100% across all platforms.  However, the rewritten method code takes
  up on average 4 times the memory.  Direct-dispatching is enabled
  by default on all platforms.

    - The direct-dispatched interpreter also supports stack-caching.
      This is enabled by default on PowerPC and ARM.

    - A further optimisation is prefetching.  This is enabled by
      default only on PowerPC.

    - In all 7 interpreter variants are possible, controlled by the
      configure options --enable-int-threading, --enable-int-direct,
      --enable-int-caching and --enable-int-prefetch.  For example,
      
      ./configure --disable-int-direct

      will revert to the indirect-dispatched interpreter as in JamVM
      1.2.4.

- Backwards compatibility with Classpath 0.13 removed (for example,
  VMSecurityManager).

- Fixed a SEGV that occurs when an abstract class does not implement
  all methods specified in the interfaces it implements, also implements
  a finalize method which is inherited by a concrete class.  When the
  VM creates the dummy "miranda" methods, the finalizer method pointer
  is left pointing to rubbish.  This occurs with the latest postgreSQL
  JDBC driver.


JamVM 1.2.4 released on 23rd January 2005
=========================================

A summary of changes since 1.2.3:

- Updated to be compatible with Classpath-0.13 and Classpath from
  CVS (as of 22nd January).

- JNI enhancements introduced in JNI 1.4 implemented (NOT using
  minimal implementation of simply returning NULL)

- Fix for setting locale when LANG is invalid (i.e. not locale-gen'ed)

- Fix for void method invocation using JNI (perform virtual method
  lookup).  This only affected methods with void return type.

- Fix for JNIEnv.  JNIEnv pointer is now constant across calls from
  the same thread.

- Implemented new VMStackWalker class, with optimised native methods.
  This class is needed for the CVS version of Classpath.

- Default system properties can now be overridden via the command
  line (using -D)

- BOOTCLASSPATH environment variable can now be used to specify
  the classpath used by the bootstrap class loader.  This overrides
  the default path.  BOOTCLASSPATH has lower priority than the command
  line and is ignored if -bootclasspath, -bootclasspath/a or
  -bootclasspath/p is used.

- NoClassDefFoundErrors thrown by the VM are now chained, and
  show the exception that caused the error.


JamVM 1.2.3 released on 23rd December 2004
==========================================

- Fix the mistake in JamVM 1.2.2 that broke Swing/AWT :)

- Sets the locale specified in the environment and defines
  System properties user.language and user.region appropriately

- PowerPC platforms : bug fix for JNI methods with very large
  numbers of arguments (e.g. 14 integer/reference arguments).

- Consistency checks for zip/jar files loaded by bootstrap class
  loader.  A bad zip shouldn't crash the VM.

- Endian check for platforms without endian.h (e.g. cygwin)

- JamVM's VM classes are now installed and loaded from a zip file
  (unless zip support is disabled in the bootstrap loader).  This
  stops old classes being left around from a previous version.


JamVM 1.2.2 released on 14th December 2004
==========================================

This release is primarily intended to align JamVM with recent changes
made to GNU Classpath's VM interface.  As of now, JamVM 1.2.2 again
works with Classpath from CVS, and Classpath-0.12.  A couple of
minor bug-fixes have also been made.

- Native methods for new VM integration class VMSystemProperties
  implemented, and changes to VMRuntime.

- Bug fix for DCONST_1 on ARM machines using mixed-endian doubles
  (bug was introduced in new interpreter).

- Added check for VFP soft-floating point on ARM (in addition to FPA).

- Bug fix for arraycopy and boolean arrays.

- Bug fix for JNI function GetStringUTFLength.


JamVM 1.2.1 released on 2nd December 2004
=========================================

- Standalone jar files can now be executed via the -jar command line option

- Updated to use Classpath-0.12 
	- Merged changes to reference VMClassLoader, reflect/Method
	- Now uses Classpath's system class loader
	- VMAccessController implemented

- 5-10% interpreter speed improvement

- Improved ARM platform support
	- Big Endian systems
	- Soft floating point

- SMP memory barriers on Intel and PowerPC

- Fix for certain Unicode chars in JNI method names

- Intel FP bug fix (Debian bug no. 260410).  Use double (64-bit) rather
  than extended (80-bit) precision

- Memory leak when two threads compete to load a class (rare race
  condition)

- Handle SIGPIPE, stopping the VM aborting.


JamVM 1.2.0 released on 9th September 2004
==========================================

- Substantially rewritten the interpreter to use "stack-caching".  This is
  an optimisation to eliminate most of the intermediate loads and stores to
  the operand stack.  On desktop PowerPC (e.g. PPC750fx, MPC7447 with large,
  on-chip L2 cache at full processor speed) it achieves a speed increase of
  between 15 and 30%.  On ARM (XScale PXA250) it achieves a speed-up of 
  50%.  Unfortunately, due to the addressing modes of the IA32 (Pentium, etc.)
  and the code produced by gcc, it is actually slower than the old interpreter!
  Because of this, stack-caching is disabled by default on IA32.

- Zip/Jar support is implemented in the bootstrap class loader.  This means
  glibj.zip no longer needs to be unzipped.  This includes resources.

- Fix for edge-conditions in floating-point to integer conversion (floating-
  point value greater than int/long range).

- Fix for very large array allocation, where the required memory overflows a
  32 bit int (fixes the SEGV with Mauve).

- Several other minor bug-fixes (e.g. ExceptionCheck was missed out of the JNI
  i/f table).


JamVM 1.1.4 released on 21st May 2004
=====================================

- JNI enhancements introduced in Java 1.2 implemented.

- Updated to use GNU Classpath 0.09.

- Pre-compiled VM classes will now be rebuilt automatically if Java sources
  change.  Fix to enable build directory to be different to source directory.

- Deprecated compiler warnings in gcc >= 3.3.3 fixed (use of cast expressions
  as lvalues).  JamVM now also builds with gcc 3.5.0.

- Minor bug-fixes and speed optimisations.

- Eclipse now starts up.


JamVM 1.1.3 released on 12th April 2004
=======================================

JamVM 1.1.3 is primarily another bug-fix release.  New functionality will
be included in JamVM 1.1.4.

- Resolution fixes to make JamVM 100% compatible with code produced
  by javac in JDK >= 1.4 and Jikes 1.19.

- New command line options -bootclasspath/a and -bootclasspath/p to prepend
  or append entries to the default bootstrap class loader.

- Default initial heap size increased to 1Mb from 256K.  "Hello World" will
  work with a heap of 75K, but this better reflects desktop application heap
  usage.  In an embedded environment -ms can be used to specify a smaller
  initial heap (e.g. -ms256k).

- Bug fix for private method invocation via JNI and reflection.

- Several other minor bug-fixes.


JamVM 1.1.2 released on 29th March 2004
=======================================

JamVM 1.1.2 is primarily a bug-fix release.  No new major functionality is
included, but many, many bugs have been fixed.  If JamVM didn't work for you
before, give this release a go!  Off the top of my head and in no
particular order:

 - Arraycopy and instanceof fixed for arrays involving different dimensions
   and Object element type

 - Array/inner class/primitive class access flags correctly set (important
   for serialization)

 - Reflection API : method invoke on interface methods now works

 - JNI : method invoke on interface methods now works

 - getResource/getResources implemented for bootstrap class loader

 - ClassLoader.findLoadedClass now handles classes initiated by a
   class loader

 - The thread contextClassLoader is now set

 - The protection domain is now set for a class

 - Many other minor bugs 

JamVM now uses VMRuntime and will now only work with Classpath 0.08.


JamVM 1.1.1 released on 25th January 2004
=========================================

- Now supports classes compiled for target >= 1.2.  In the past, javac inserted
  synthetic methods for interface methods not implemented by abstract classes.
  These are not produced if javac is used with -target 1.2, which is now the
  default with JDK 1.4.  JamVM now inserts these methods if they are not
  supplied by the compiler.
  
- Class loader changes.  JamVM now records initiating loaders so user-defined
  class loaders should be referred to less.

- Updated to use classpath 0.07.

- Java 2 style application class loader/bootstrap class loader split
	 - new command line options -bootclasspath and -classpath (or -cp)
	 - Jar and Zip archives can now be specified in the classpath.

- bug fixes (integration of Classpath 0.06 in JamVM 1.1.0 broke instanceOf)

- Re-worked stack overflow handling.  Previously, the first thread overflow
  would be trapped, but further overflows would not.  A thread may now catch
  StackOverflowException and repeatedly overflow.


JamVM 1.1.0 released on 17th November 2003
==========================================

There's been quite a few changes, including performance improvements and more of
the specification is now implemented (should be everything now but Runtime.exec),
as well as the usual bug-fixes.

- Interface method tables are now implemented.  This means an interface method
  invocation should now be almost as fast as a normal virtual method.

- The full Reflection API is implemented (Constructor, Field, Method, etc.)
  with primitive widening and wrapping and inner class support.

- Updated to use Classpath-0.06 rather than 0.04 (note JamVM won't work with
  0.04 anymore).

- Ported to the ARM architecture.

- Re-worked exception printing - now supports 1.4 style StackTraceElements.

- Interpreter optimisations (more "fast" bytecodes).

- Command line system properties can now be specified (-Dname=value).


JamVM 1.0.0 released on 12th March 2003
=======================================

- INITIAL RELEASE