J2SE 1.2: Codename Playground
next milestone for Java came in 8th December 1998. This version had:
can clearly see how fast Java grew in just three years. During this time, Sun also
introduced a new terminology to describe Java technology—Java SE (Standard
Edition). The name JDK is still used to describe an implementation of this
Introduction of Swing
major feature introduced in Java 2 was Swing—the new Java-based GUI classes.
This made the earlier AWT classes somewhat obsolete, except that Swing extended
those classes. AWT components are considered heavyweight because they use many
native operating system calls. The new Swing-based GUI classes are totally Java
based and therefore are lightweight. These Java based classes
provided the advantage of on-demand installation in browsers that refused to
add support to the new JDK versions; this was the case with Microsoft’s
Internet Explorer (readers may be aware of the famous legal suit between
Microsoft and Sun Microsystems during this period). Swing classes also
permitted the “pluggable look and feel” (PLAF) that allowed developers to change
the look and feel of their applications to whatever they would like. Swing supported
Windows, Motif, and Java native platforms.
JDK now included classes for the 2D API to allow the user to create
two-dimensional charts and graphs easily with the help of several predefined
classes and interfaces. The 2D API is the basis for all the drawing in the Java
SE platform, not just for charts and graphs.
1.2 introduced the drag-and-drop facility for selecting contents in a Java
application and then dragging and dropping them into a native application, and
vice versa. Thus, we could now drag and drop the contents of a Microsoft Word
document into a Java application, as well as the other way around. This is done
without copying and pasting the contents to a clipboard.
JDK now provided classes for playing back MIDI files and a full range of .wav,
.aiff, and .au files. It also provided much higher sound quality.
IDL is CORBA’S ORB (Object Request Broker) implemented on the Java platform.
This facilitated integration of Java applications with existing CORBA clients
and servers. Java provided both CORBA IDL (Interface Definition Language) to
Java Interfaces mapping and Java to CORBA IDL reverse mapping. This made it
possible to protect the investments in both existing Java Client and RMI-based
security is now policy based. Digital signing was introduced in JDK 1.1. This
allowed the identification of the applet source; however, it was not possible to
assign different privileges, depending on the source of the applet. In other
words, there was no differentiation between two different trusted applets or
between a trusted applet and a stand-alone application. All would acquire the
same privileges. J2SE 1.2 resolved this issue by creating policy-based security.
One can now define a security policy based on the source of the applet. In this
way, different applets would be subject to different policies defined by their
user and thus acquire different sets of privileges. This also applies to
stand-alone Java applications that were also subject to user-defined policies. The
policy files are text based and easily configurable. Java also provided a
policy tool to create and maintain policies. The policies enabled the
fine-grain access control to system resources.
addition to the aforementioned major changes, several enhancements were made to
improve performance in general. The loaded classes now had better memory
compression. The memory allocation and garbage collection had improved
algorithms for faster allocations and deallocations. The Just-in-Time (JIT) compiler
mentioned earlier was introduced in this version of Java. New classes such as ArrayList and BufferedImage and APIs such as
Collections were added. DSA code signing was also added.