NEWS/ChangeLog for rJava -------------------------- 1.0-12 2024-01-26 o Win32: minor changes to adapt to (undocumented) API changes in R 4.2.0. o Win32: warn if R_HOME path is too long. o dispatch on superclasses when converting native types in the reflection API (J/.jrcall). Please note that it is safer to use the native API than to rely on reflection conversions so packages are encouraged to use the native API which is much faster and type-safe. (#317) o remove JavaDoc from the distribution tar ball due to security issues (#303). Note that JavaDoc can be generated from the source package by running `make javadoc` in the `src/java` directory. o bugfix: .jarray(..., dispatch=TRUE) was generating nested arrays with incorrect content if the input array had more than two dimensions. (#5) o the IGNORE env var was misspelled in configure.win. (#304) 1.0-10 2023-11-30 o minor documentation fixes o fix format specifier in an error message 1.0-9 2023-11-28 o clean up benign C warnings 1.0-8 2022-12-30 o attempt to prevent (close to) infinite loop in stack detection due to unwanted tail call optimization by gcc >= 11 if JDK older than Java 10 is used. (#300) 1.0-7 2022-04-29 o fix conversion from native encoding into UTF-16 (introduced in 1.0-2) to work correctly if the native encoding is neither UTF-8 nor Latin1. (#228) o debugging: if DEBUG_ENCODING C macro is defined string conversion routines will output debugging information when strings are converted between R and Java. o JRI: console callbacks (Read/WriteConsole) encode and decode strings between native encoding and Java. (#24) Previously, only UTF-8 native locales were supported. o Replaced deprected constructors like new Double(double) with valueOf() calls to make recent JDKs happy. o Work around a crash in RStudio on UCRT Windows. (#296) o add .jvmState() reporting the state of the JVM. (#259) 1.0-6 2021-12-10 o remove obsolete autoconf macros o JRI 0.5-7 changes: - add support for JRI_CPPFLAGS and JRI_LIBS variables which allow specific flag overrides in JRI only - use config.h in jri.h (except for Windows) - add header checks needed for R_ext/eventloop.h (#284) - update automake tools 1.0-5 2021-09-24 o allow access modifications to fail on JDK-17 == Important note to Java developers: JDK-17 no longer allows access overrides, so J() wrapper will fail for cases where the underlying class does not allow public access. This means that it is no longer possible to write high-level code that behaves as if it was a member of the class. Do not upgrade to JDK-17 if that is important in your application or write a Java wrapper that exposes the necessary fields/methods as public. 1.0-4 2021-09-03 o make jverify() check the object type before checking for serialization content. This fixes possible segfaults, including one in .jfield() when used on jclassName objects where jverify() was used on the wrapping S4 class. 1.0-3 2021-04-16 o update URLs referring to Java docs to current 1.8 website 1.0-2 2021-04-15 o convert UTF-16 surrogate pairs to UTF-8 when retrieving strings from Java to R (#51) o use UTF-16 encoding when converting R strings to Java o avoid warnings in the "blah" R Windows API by casting to different types on Windows and unix. 1.0-1 2021-04-12 o New feature: support for custom class loaders. It is strongly recommended that package authors that use rJava in their package use this new feature since it avoids conflicts of classes in packages. (#250) The main mechanism is the own.loader=TRUE option in .jpackage() which instantiates a new, clean class loader for a package such that it is not affected by subsequent class path changes by the user or other packages. In order to use it, the package has to use class.loader=.rJava.class.loader in calls to functions that need to load classes such as .jnew() or J(). This can also be done automatically via something like J <- function(...) rJava::J(..., class.loader=.rJava.class.loader) in the package without need to change every call to J() separately. See the documentation for .jpackage() for details. o J() will automatically call .jinit() if rJava has not been initialized yet. o .jchar(x) supports single non-NA string by calling the String$toCharArray() method. o raw vectors were not recognised in J() API (#260) 0.9-14 2021-02-04 o JRI: fixed detection of the major Java version (#239) o JRI: support Java major versions with suffixes like 13-ea (#236) o JRI: Windows: flags sources as 1.8 to support Java 14 and higher where changes in the language break old code (#241) o Fixed compilation of JRI on macOS to not require the JavaVM framework, but rely on flags from R CMD javareconf. This avoids breakage on macOS 11 which no longer provides JavaVM in the SDK. (#248) 0.9-13 2020-07-06 o increase default JVM stack size by adding -Xss2m to JVM parameters unless -Xss is already specified in .jinit(). This is an attempt to address stack overflow problems in Java 11 and higher on some platforms which appear to use very small stack sizes. (#224) o re-define EXTPTR_xx macros to avoid ABI breakage between R 4.0.0 and later R 4.0.x versions. o add missing C entry points to the symbol cache. (#221) o disable dynamic symbol lookup to catch any (inadvertent) use of unregistered symbols. 0.9-12 2020-03-23 o rJava has a new option --enable-dynload which enables rJava to load JVM dynamically at run-time. It is only supported on unix platforms at this point and is enabled by default on macOS. When enabled, rJava library does not link to JVM, but instead assumes that the JVM library will be loaded into R before JVM functions are used. The default initialization uses the following order to find JVM at run-time: - use JAVA_HOME (typically set by R CMD javareconf) - call /usr/libexec/java_home (if JAVA_HOME is not set) Find ${JAVA_HOME}[/jre]/lib/server/libjvm.{so|dylib} If not found, Java cannot be loaded. On Windows the order has not changed: getOption("java.home"), JAVA_HOME environment variable and registry. However, if the Java home setting is specified, it must be a valid directory, otherwise a warning is issued (#209) and it is assumed to be "" and thus the search continues in the registry. o convert class names from Java objects into JNI notation when constructing method signatures. (#81) o fix a bug in .jfield() which prevented accessing static fields if rJava class loader was not present yet (only affected initialization). o modify bootstrap to avoid reflection calls which are broken in Java 12 (see #175 and https://bugs.openjdk.java.net/browse/JDK-8221530). o added .jgc() to run JVM garbage collector (#180) o fix filtered .jfields() to return actual values (#213) o .jfields() and .jmethods() now correctly filter results even for as.obj=TRUE (#212). Filtering is done by retrieving the names and applying the regular expression specified in `name'. 0.9-11 2019-03-27 o fix segfault if en exception is thrown during rJava initialization (#177) o disable Java stack workaround if loaded from a JVM process (#130) o bump JVM target to 1.8 for JDK 12 and higher since such target is no longer supported (#174). o fix HAVE_XRS detection (#168) o Windows: fix build if javah.exe is missing (#157) o Windows: detect JAVA_HOME correctly from registry even if the key is using JDK instead Java Development Kit (#120) o Windows: don't fail if `RuntimeLib` registry entry is missing (#163) 0.9-10 2018-05-29 o support builds with JDKs that are missing javah (#141) o detect JDKs that don't call themselves Java (such as openjdk) (#146) o macOS: pre-load libjvm.dylib to avoid issues with incorrect ID in Oracle's released binaries 0.9-9 2017-10-11 o add support for --disable-Xrs configure option in case java -Xrs is so broken that it cannot even be tested - reportedly the case with Docker (see #63). o add optional class.loader= argument to .jnew() which allows to use a custom loader in special cases. o change target to 1.6 and higher since Java 1.9 breaks when asked to compile anything older than that. There is no technical reason, so you can still build 1.2/1.4 targets by reverting 992828b and using a JDK that won't break on 1.4 targets. o Process events on Windows while in rniIndle. (#23) o Work around a bug of Oracle's Java on Linux which caps the stack of R at 2M. (#102) The bug leads to segfaults in recursive computations (not an R error as R doesn't know the stack size has been reduced). The workaround can be disabled via environment variable RJAVA_JVM_STACK_WORKAROUND=0, which may produce better results with memory access checkers (ASAN, valgrind), because the workaround detects the new stack size by trying to access inaccessible memory. This JVM behavior was a workaround for an issue in old Linux systems (JDK-4466587) and is going to be fixed in Java 10. o Work around a change in registry location on Windows for Oracle Java 1.9. (#120) 0.9-8 2016-01-06 o Work around a bug on Oracle's Java on OS X by pre-loading jli o Work around DYLD_FALLBACK_LIBRARY_PATH being dropped in OS X 10.11 0.9-7 2015-07-27 o explicitly set -classpath in configure for getps since the user may have set CLASSPATH and thus override the default (see #3) o when constructing String references from character vectors, treat NA as null on the Java side (see #15) o add .jsimplify(..., promote=TRUE) option to promote int to double if integer NAs are to be interpreted literally as -2147483648 values. (see #39) o fix .jarray(.jshort(...)) to respect the `jshort` tag (see #40) 0.9-6 2012-12-23 o bugfix: the first JVM parameters was shadowed by headless mode parameter if enabled (default on OS X). 0.9-5 2012-12-03 o add more debugging information in RJavaClassLoader to trace cases where class path entries are invalid or discarded o detect support for -Xrs and enable it by default (this prevents Java from killing R process on interrupt) o restore locales after Java initialization (some JVMs clobber locales with incompatible settings). o add --enable-headless option which sets the java.awt.headless to true. In the auto mode this flag is only enabled on Mac OS X. Note that it is only set upon initialization, it does not affect already running JVMs. 0.9-4 2013-03-11 o added support for unboxing of Double[], Integer[] and Boolean[] to .jevalArray(.., simplify=TRUE) and thus also to .jcall() o Windows: add Java configuration paths before existing PATH entries o Windows: honor a new option "java.home" to override JAVA_HOME environment variable and system settings to allow co-existence of other tools that may require different Java paths. o Windows: fix a buglet in error reporting when no Java is installed o raise an error if the number of arguments to a Java call exceeds maxJavaPars. Previously, calls would be silently truncated. Note that maxJavaPars can be raised by compiling rJava, e.g. with: PKG_CFLAGS=-DmaxJavaPars=96 R CMD INSTAL rJava_... 0.9-3 2011-12-10 o bugfix: .jinit() was failing on Java 1.4 with "cannot obtain Class.getSimpleName method ID" since the method is only present in Java 1.5+ This was inadvertent, rJava aims to support Java 1.2+ 0.9-2 2011-10-26 o When NOAWT is set, rJava will enable headless mode in the JVM by setting the java.awt.headless property to true during initialization in .jinit() o All C-level entry points are now pre-cached when rJava is loaded such that calls can be made much faster since symbols don't need to be looked up. This should speed up calls to methods that take very little time as well as other parts such as checking for exceptions. 0.9-1 2011-06-28 o fixed Java detection from registry on Windows (bug introduced in 0.9-0) 0.9-0 2011-06-22 o fixes issues introduced by several new features in the late 0.8 series. Most importantly .jarray() and .jevalArray() behave as intended (and as implemented in previous versions). The same applies to .jcall() behavior with respect to arrays and its evalArray argument. The defaults for some new arguments have been changed to reflect the original behavior. o .jevalArray() has an additional argument `simplify' which allows multi-dimensional arrays to be converted to native R types. Use with care - it may convert more recursive types in the future so it should be used preferably where you have control over the types converted. o fixed a bug in .jevalArray that was not simplifying string vectors correctly when the array type was not specified (.jclass returns dot notation whereas signatures use JNI notation so a conversion was necessary) o use install.libs.R in R 2.13.1 to install multi-arch JRI 0.8-8 2010-12-20 o Add support for r.arch in RJavaClassLoader on Windows as well o javaImport was only able to import java packages from the system class loader (not from additional jars) 0.8-7 2010-10-18 o Windows updates to accommodate changes in R 2.12 and layout changes in recent Sun Java installations. 0.8-6 2010-09-17 o JRI 0.5-4: rniStop() provides several ways to notify R on unix. It improves handing of user interrupts via rniStop() by allowing to avoid signals (signals can cause problems in some recent JVM implementations). 0.8-5 2010-09-02 o fix a bug introduced in 0.8-2 where .jclassPath() would not show the real class path o if the rJava class loader is used as a primary loader it will also register as the context class loader. Some projects rely on the thread context class loader instead of Class.getClassLoader() [which is still more reliable] so those will now work as well. o JRI 0.5-3 (bugfixes) 0.8-4 2010-04-28 o JRI 0.5-2 IMPORTANT NOTE: handling of NAs in character vectors has been fixed, NAs were incorrectly passed as "NA" from R to Java instead of nulls (it was correct the other way round). Any code that relies on such incorrect behavior will need to be fixed! Other changes in JRI are mostly related to Windows support (bugfixes R 2.11.0 and Windows 64-bit support) o run.bat is now installed as part of JRI 0.8-3 2010-03-16 o REngine and JRIEngine classes are now included in rJava/JRI although they are not loaded by default. o .r2j now has convert parameter to allow the creation of pure references (convert=FALSE) o toJava() is a new function equivalent to .r2j but resulting in REngine API references (instances of REXPReference). By default the references are not resolved since the primary use is to pass R functions to Java for callbacks. o set text mode for stdin on Windows (thanks to Brian Ripley) o fix support of NULL arguments in new(J("SomeClass"), ...) o fixed issues in with() and within() when used on jobjRef; also the evaluation environment is now the parent frame as expected o disable AWT tests if NOAWT is set; enable a few more tests 0.8-2 2010-01-22 o faster class loader implementation o added support for 64-bit Windows (thanks to Brian Ripley) 0.8-1 2009-10-30 o fixed exception handling on Windows: the access to "call" was off for Windows builds causing incorrect "call" entries in exceptions which broke when encountered in try(). o fixed .jcall() which had inadvertently the default for use.true.class argument set to TRUE. That is considered a bug since it breaks the original behavior and is against the idea of .jcall being the low-level interface. 0.8-0 2009-10-27 o new exception handling was introduced: Java exceptions are mapped to Exception conditions which can be used to catch the exception at R level using e.g tryCatch. The class name automatically contains "Exception", "error" and "condition", as well as all the names (without package path) of the classes in the inheritance tree of the actual class of the Exception. This allows targeted handlers: tryCatch(.jnew("foo"), NoClassDefFoundError=function(e) ...) In addition JNI code now causes an error instead of a warning, however, some errors internal to JNI may not have an associated Java exception and thus will fire the usual simpleError condition. As a consequence of the new error handling exception objects are now supplied in e$jobj of the handler and .jgetEx() becomes obsolete. o added new high-level API using the "J" function. It replaces the previously used .J()/.jrnew() and .jrcall(). New Java objects are created using new(J("class"), ...) and static methods and fields are accessed using J("class")$... The corresponding implementation uses reflection in all cases. An additional class "jclassName" was created to support static calls to accessor methods such as $ and calls to new(). o [RF] arrays are now split in two classes : "jrectRef" for rectangular arrays, similar to R arrays, and jarrayRef for rugged arrays. Indexing of all arrays is supported using the double bracket indexer "[[" and "[[<-" The single indexer "[" is only currently implemented for rectangular arrays. This is experimental. Replacement ([<-) is not supported yet. o [RF] with.jclassName and within.jclassName is added to support "with" semantics on static fields and methods of java classes. Double <- J("java.lang.Double" ) with( Double, parseDouble( "10.2" ) ) o [RF] length.jarrayRef queries the number of objects in a java array. An exception is generated if the object is not an array. Also array$length can be used similarly to array.length in java o [RF] .jcast gains arguments "check" and "convert.array". Their default value is FALSE for backwards compatibility with previous releases of rJava o [RF] Binary operators <, >, <=, >= to compare two objects where at least one is a java object reference. d <- new( J("java.lang.Double"), 0.0 ) d < 1.0 d < 1L Comparison of arrays is not currently supported o [RF] lapply and sapply may now be used on Iterable java objects such as Vector and java arrays. see ?as.list.jobjRef o [RF] The generic "clone" function is added, and an implementation for java objects. an Object must implement the Cloneable interface, otherwise an exception will be raised. Furthermore, careful reading of the java documentation of Object#clone is recommended since this is not standard java behaviour. Currently "clone" is not supported on arrays o [RF] A mechanism for "attach"ing java packages has been introduced, following the mechanism of the RObjectTables package from the OmegaHat project. This allows to "attach" a set of java package paths to R's search path: > attach( javaImport( "java.util", "java.lang" ) ) and then use classes from this package like this : > new( Vector ) > new( HashMap ) > new( Double, 10.2 ) > new( Integer, 10L ) > Collections$EMPTY_MAP This feature is currently __very__ experimental and is as dangerous as any other use of attach 0.7-1 (never released) o [RF] added .J high-level java constructor (based on reflection as opposed to complete match as .jnew does) o [RF] added .jinstanceof and instanceof operator o when loaded into another JVM (e.g. via JRI), rJava would crash on any call if .jinit() was missing. Now it correctly reports the error. o fixed synchronization issues in both JRI and REngine 0.7-0 2009-08-22 o fixed bug in $ getter of fields using old .jfield API o fixed a bug in .jevalArray which failed when the signature was specified directly (and subsequently .jfield failed in most cases) o improve speed of reflection-based API (.jrcall and `$') by using native array support in rJava o reflection API now returns NULL invisibly for void results o try to find the best match in reflection-based API using internal Java code (code and idea by Romain Francois) o added with() method for jobjRef (by Romain Francois), see http://romainfrancois.blog.free.fr/index.php? post/2009/06/17/with-semantics-for-java-objects-in-rJava o added names() method for jobjRef to facilitate code completion (based on code by RF: http://tr.im/w33B) o update to JRI 0.5-0 0.6-3 2009-06-14 o update to JRI 0.4-3 (adds REngine API, enhanced support for environments and references) o allow signatures longer than 256 bytes o added lib.loc parameter to .jpackage() 0.6-2 2009-01-26 o fix --enable-debug to really enable debug code o improve Windows setup (add only paths if they are not already listed and check their presence first) and warn if the system suffers from PATH truncation bug (or PATH is truncated in general) 0.6-1 2008-12-23 o substitute $(JAVA_HOME) in configuration flags when necessary o flag generated strings as UTF-8 and convert incoming strings into UTF-8 (see note in ?.jcall for details) This should improve interoperability in non-UTF-8 locales (most prominent example is Windows) 0.6-0 2008-09-22 o add support for object cache - see .jcache() - based on Java serialization 0.5-2 (never released, turned into 0.6-0) o add direct support for raw vectors as method parameters (before .jarray(r) had to be used) o add .jserialize() and .junserialize() functions for Java-serialization (do not confuse with R serialization!) 0.5-1 2007-11-05 o fix crashes in Windows when Java calls the vfprintf hook o enhance Java environment checks, add more specific errors o add support for r.arch system property which allows multi-arch support on platforms that don't have fat binaries (e.g. Linux) 0.5-0 2007-08-22 o **API CHANGE** The order of arguments of .jfield has been changed to match the order used in .jcall and the return value is as expected and doesn't need .jsimplify anymore. o The implementation of .jfield no longer uses reflection it supports static fields and .jfield<-() was added. o Consolidate interface code for static/non-static calls. It is now possible to call a static method using a non-static object. o Add .jpackage function for initialization of Java packages. See documentation for details, packages should no longer use .jinit in their initialization code. o Add preliminary JRI support from R (see .jengine) o Prepare hooks for de-serialization o Add support for short Java type o Add support for converters o Fix R-devel compatibility issues o Fix a memory leak in string array handling o Use Java settings from R for compilation o Add a custom class loader o Fix a bug in .jcastToArray that produced invalid signatures o Added support for [Z in .jevalArray o Fix a bug in .jarray missing [ prefix for native type arrays 0.4-13 2007-01-14 o Fix Java-side memory leaks (temporary parameters to methods were not properly released, thanks to Erik van Barneveld for supplying a reproducible example). o Fix a bug that caused only the first VM parameter to be passed on during initialization (thanks to Bernard Rosman for reporting). o .jmkref now accepts plain class names (with .) o Fix bug in .jarray (and underlying RcreateArray) that was returning wrong class name if the contents class was an array. o Add --enable-callbacks option to configure (disabled by default). The callbacks support is currently incomplete and experimental. o Update URL to http://www.rforge.net/rJava/ o Update to JRI 0.3-7 (LCons, createRJavaRef, assign XT_NONE) 0.4-12 2006-11-29 o Added documentation for .jthrow, .jclear and .jgetEx and a bugfix in .jgetEx o rJava now uses a namespace. This is still somewhat experimental, because rJava needs to perform some dirty tricks to unseal the namespace during initialization. Please test and report! o Update to JRI 0.3-6 (GIJ fix and fix for R-devel interface changes) 0.4-11 2006-10-10 o Replace variadic macros with wrappers (for compilers that don't support ISO C99). o Modify JNI error reporting - use warnings instead of direct stderr. o Update to JRI 0.3-5 0.4-10 2006-09-14 o Removed obsolete JNI 1.1 support that is no longer provided in JDK 1.6 and thus prevented rJava from being used with JDK 1.6 o Update to JRI 0.3-4 (change compilation to force Java 1.4 compatibility even when more recent JDK is used) 0.4-9 2006-09-12 o Update to JRI 0.3-3 which fixes API version mistake which 0.4-8 2006-09-11 o Added --enable-jri=auto option which will build JRI only if R shared library is present. It is now the default. o Update to JRI 0.3-2 (added boolean support) 0.4-7 2006-09-05 o .jevalArray now works with Java objects that have not been cast to a Java array explicitly. The function is now also documented properly. o Added .jgetEx and .jclear functions for querying and clearing of Java exceptions/throwables. o Added .jthrow to allow throwing of exceptions from R code. o Fixed a typo in .jrcall when handling string return values. 0.4-6 2006-08-20 o Fixed bug in initialization on Windows, introduced in 0.4-4 0.4-5 2006-06-24 o Added support for scalar bytes as .jbyte (byte arrays are still natively represented as RAW vectors) o Added .r2j function which allows to push R objects into Java as references. This works only if R is run via JRI, because it requires a working Rengine instance. 0.4-4 2006-06-21 o Fixed bug that prevented loading into existing VM if the classpath contained duplicate items. .jmergeClassPath now filters out duplicate paths. o .jcall and .jnew discard all named parameters that are passed as `...'. Named parameters are now reserved for future call options o Converted all S3-methods into S4 methods. Also `show' is now used instead of `print' and the output format was changed. o Prototype for jobjRef is now a valid null-Object o Added .jequals and corresponding ==, != op methods. Currently == and != operators feature the same behavior as .jequals(...,strict=FALSE), i.e. scalar non-Java objects are converted into Java objects if possible and then compared, so s <- .jnew("java/lang/String","foo") s == "foo" # returns TRUE o Added .jinherits which allows to check Java-side inheritance using JNI (= isAssignableTo). o Added .jfindClass and .jclassRef that return Java class object o Added check parameter to .jcall and .jnew that allows the caller to prevent implicit call to .jcheck It is mainly useful in cases where silent operation is desired (e.g. in conjunction with try). Additionally, silent parameter was added to .jnew o Added is.jnull which is like is.null but also returns TRUE if the supplied Java object is a null-reference o Added jlong class and .jlong function. Those were documented in the tutorial but never really implemented. Still, they may not be supported in all parts of rJava. WARNING: conversion between Java's long and R's jlong is lossy! R stores jlong in doubles so the conversion implies loss of precision. 0.4-3 2006-05-16 o improved, documented and fixed handling of fields .jfield is dedicated accessor with more options 0.4-2 2006-05-08 o Update to JRI 0.2-5 (no change in rJava) 0.4-1 2006-05-05 o Fixed bug in Windows initialization 0.4-0 2006-05-03 o JRI is now included in rJava 0.3-9 2006-04-20 o fixed a minor bug in Rglue.c that may prevent older compilers from compiling it. 0.3-8 2006-04-17 o .jinit has an additional parameter 'parameters' that allows users to pass additional parameters to the VM (such as -X...) o .jinit now uses a hack (defined in .jmergeClassPath) that allows us to modify the class path of a running VM. This may or may not work for a specific VM, because it is an ugly hack exploiting some implementational features of the VM. See .jmergeClassPath source for reference and explanation. o .jarray now supports the use of .jarray(x) where x is a Java reference. The documentation requires you to use .jarray(list(x)), but since the use of .jarray(x) seems to be a very common mistake, we may as well silently support it. o .jarray has an optional parameter contents.class which allows the global specification of the class type for arrays of objects. (Untested, use with care! In most cases .jcast is probably what you really want.) o Added some more support for floats, longs and byte arrays. (Again, untested) 0.3-7 2006-01-31 (non-public release) o New, experimental feature has been added - JNI cache. This feature can be enabled by passing --enable-jni-cache argument to configure. Normally, each time we access JVM we retrieve new JNI environment to make sure there are no threading issues. In single-threaded environment this is superfluous, so we may as well cache it. The idea is to reduce the overhead. However, the gain is not as huge as expected, so it is not enabled by default. Also note that threads and jni-cache are mutually exclusive. o Another even more experimental feature has been added - support for threads. This feature is enabled by using --enable-threads configure argument. When threads support is enabled, JVM is started on a thread separate from the main thread. Some implementations of AWT classes require this. However, it is not always safe to use, because R event loop is unaware of the separate thread and can deadlock it. 0.3-6 2006-01-30 0.3-5 2006-01-02 0.3-4 2005-12-28 0.3-3 2005-12-20 0.3 2005-12-19 o finalizers, arrays 0.2 2005-09-03 o S4 classes 0.1 2003-08-26 o initial release