The following topics are covered:
The Parallel Array Sorting feature adds the same set of sorting operations currently provided by the Arrays class, but with a parallel implementation that utilizes the Fork/Join framework. Additional utility methods were added to java.util.Arrays that use the JSR 166 Fork/Join parallelism common pool to provide sorting of arrays in parallel. The methods are called parallelSort() and are overloaded for all the primitive data types and Comparable objects. See JEP 103 for more details.
The new methods are mentioned in the Java Tutorials (see Arrays and Fork/Join).
Base64 class
defines factory methods to get Encoder and
Decoder
instances that encode and decode base64 data. Base64Sample and Base64Sample2 are code samples that
demonstrate the Base64 class. See JEP 135:
Base64 Encoding and Decoding for more details.
Methods were added to the Java Libraries to support unsigned
integer arithmetic. Integers are 32-bits numbers out of which 1 bit
is reserved for the sign but using these unsigned methods one can
use all the 32 bits. Static methods such as
parseUnsignedLong, toUnsignedString,
divideUnsigned,
compareUnsigned were added to the Long class and
methods such as divideUnsigned,
compareUnsigned,
parseUnsignedInt,
remainderUnsigned, toUnsignedString
were added to the Integer class.
These methods are faster than using the BigDecimal and
BigInteger for
arithmetic opearations as these include optimizations of primitive
datatypes.
Area: Core Libraries / java.lang.reflect
Synopsis: The java.lang.reflect.Proxy(InvocationHandler h) constructor now throws a NullPointerException if the given InvocationHandler parameter is null.
Nature of Incompatibility: behavioral
Description: Existing code that constructs a dynamic proxy instance with a null argument will now get NullPointerException. Such usage is expected to rarely exist since a null proxy instance has no use and will throw a NullPointerException when its method is invoked anyway.
RFE: 4487672.
In addition, the following enhancements are introduced:
Area: API: Language
Standard/Platform: Java SE 7
Synopsis: Class loading can be prone to deadlocks if custom
class loaders do not adhere to an acyclic class loader delegation
model. New APIs have been added to the
java.lang.ClassLoader class to support parallel loading of
classes and finer-grained locking mechanism for class loading
operations. Custom class loaders which would like to leverage this
functionality must refer to the
Class Loader API Modifications for Deadlock Fix documentation
for the suggested model and requirements and be implemented
accordingly.
Area: API: Language
Standard/Platform: JDK 7
Synopsis: Previously, the two exception types in the
javax.lang.model.type package,
MirroredTypeException and MirroredTypesException,
were unrelated. In the javac implementation,
MirroredTypeException was thrown where
MirroredTypesException should have been thrown. In part to
address this problem, MirroredTypeException was made a
subclass of MirroredTypesException. This change is binary
compatible and generally preserves the behavior of existing
annotation processors. However, it is possible this change may
cause source incompatibilities for client programs; in those cases,
changing the order of catch clauses should allow the programs to
compile again.
Area: API: Language
Standard/Platform: JDK 7
Synopsis: To model the language changes in this release,
several updates were made to javax.lang.model.* including
adding a method to the javax.lang.model.type.TypeVisitor
interface. Such an addition is source incompatible with libraries
that have directly implemented the TypeVisitor interface.
However, such additions were foreseen as part of this API's
evolution and libraries were explicitly cautioned to extend one of
the utility visitors instead of directly implementing such an
interface.
RFE: 6933147
Area: API: Language
Standard/Platform: JDK 7
Synopsis: The method
Runtime.exec(String command, String[] envp, File
dir) breaks the command string into tokens, consisting
of the name of the executable and its arguments, by the invocation
new
StringTokenizer(command) with the default delimiter set
(the space character, the tab character, the newline character, the
carriage-return character, and the form-feed character).
Essentially, this method splits the command string into tokens,
using white space as the delimiter.
On Windows operating systems, splitting the command parameter by
white spaces can lead to errors. In particular, if the
command parameter contains an executable path with
spaces, the invocation new StringTokenizer(command)
extracts the wrong executable name. For example, the invocation
Runtime.getRuntime().exec("C:\\My Programs\\foo.exe
bar") attempts to launch the program C:\My with
the arguments Programs\foo.exe and bar.
This invocation is likely to fail with an exception to indicate
that the executable C:\My cannot be found.
If your legacy application is not using a security manager (see the
class SecurityManager),
you can specify the system property
jdk.lang.Process.allowAmbigousCommands with any value
other than false so that the method
Runtime.exec correctly parses path names with spaces.
(See
System Properties in The Java Tutorials.) Alternatively, you
can surround the path name with quotation marks. For example, the
invocation Runtime.getRuntime().exec("\"C:\\My
Programs\\foo.exe\" bar") attempts to launch C:\My
Programs\foo.exe with the argument bar.
Note: For updates after Update 25, the name of the
system property to allow ambiguous commands is
jdk.lang.Process.allowAmbiguousCommands.
Area: API: Utilities
Standard/Platform: JDK 7
Synopsis: Due to an error in java.util.TreeMap, it
was previously possible to insert invalid null elements and
elements not implementing Comparable into empty
TreeMaps and TreeSets. Only a single invalid
element could be inserted into the empty TreeMaps or
TreeSets; additional elements would cause the expected
NullPointerException or ClassCastException. Most
other operations upon the collection would also fail. As of JDK 7,
inserting an invalid null element or an element not implementing
Comparable into an empty TreeMap or
TreeSet throws a NullPointerException.
RFE: 5045147
ProcessBuilder class provides a more
convenient way to invoke subprocesses than does
Runtime.exec. In particular, ProcessBuilder makes it easy to
start a subprocess with a modified process environment (that is,
one based on the parent's process environment, but with a few
changes).java.lang.Thread class has
the following enhancements:
Thread.State
enum class and the new getState()
API are provided for querying the execution state of a thread.getStackTrace
and getAllStackTraces
methods in the Thread class - provides a programmatic
way to obtain the stack trace of a thread or all threads.uncaughtExceptionHandler mechanism, previously
available only through the ThreadGroup class, is now available
directly through the Thread class.sleep() method is provided which
allows for sleep times smaller than one millisecond.java.lang.instrument
package provides services that allow Java programming agents to
instrument programs running on the Java virtual machine by
modifying methods' bytecodes at runtime.Formatter class provides support for layout
justification and alignment, common formats for numeric, string,
and date/time data, and locale-specific output. Common Java types
such as byte, java.math.BigDecimal
, and java.util.Calendar
are supported. Limited formatting customization for arbitrary user
types is provided through the java.util.Formattable
interface.java.util.Scanner class can be used to convert text
into primitives or Strings. Since it is based on the
java.util.regex
package, it also offers a way to conduct regular expression based
searches on streams, file data, strings, or implementors of the
Readable
interface.split methods are new. The
subSequence method has been added, as required by the
CharSequence interface that String now
implements. Three additional methods have been added:
matches, replaceAll, and
replaceFirst.subSequence method has been added, as required
by the CharSequence interface that
StringBuffer now implements.interrupt method has been revised to interrupt
threads blocked in channel-I/O operations.java.util.prefs,
allows applications to store and retrieve user and system
preference and configuration data. This data is stored persistently
in an implementation-dependent backing store. The Preferences API
is intended to replace most common uses of class
java.util.Properties, rectifying many of its
deficiencies, while retaining its light weight.java.lang.StrictMath
- Class java.lang.StrictMath has the same API as old
class java.lang.Math, which was present in previous
versions of the Java platform. Unlike class Math,
however, StrictMath is defined to return bit-for-bit
reproducible results in all implementations.java.lang.Math
- Class java.lang.Math provides the same set of API as
does class StrictMath. However, unlike some of the
numeric functions of class StrictMath, all
implementations of the equivalent functions of class
Math are not defined to return the bit-for-bit same
results, but can vary within specified constraints. This permits
better-performing implementations where strict reproducibility is
not required.Countdown.java is a
simple demo application that uses the Timer API.java.lang.Runtime to
provide a simple and portable interface to these facitilies. The
new methods are:
In addition, the Runtime.exit
method has been revised. For more information, see Design of the Shutdown Hooks API.java.util.zip and
java.util.jar have been enhanced with the addition of
the following:
java.util.zip.OPEN_READjava.util.zip.OPEN_DELETEjava.util.zip.ZipFile(File file, int mode)java.util.jar.JarFile(File file, boolean verify, int
mode)JarURLConnection creates a temporary local file that
holds Jar-file date, and a JarFile object is created on top of the
temporary file. Because the open file handle/descriptor on each
temporary file was never closed, the files could quickly take up
disk space for long-running server applications. The new API
provides a solution for this problem by supporting a new
"delete-on-close" mode for opening Zip and Jar files.