Although Java 1.1 is a massive new release, there are relatively few
changes to the Java language in this version. The new features of the
language are quite significant, however, as they add useful
functionality and make the Java language even more elegant. Here is a
brief summary of the new features of the Java language in Java 1.1:
- The addition of inner classes is the largest change to the Java
language in Java 1.1. With this new feature, classes can be defined as
members of other classes, just like variables and methods. Classes can
also be defined within blocks of Java code, just like local variables.
A class that is declared inside of another class may have access to
the instance variables of the enclosing class; a class declared within
a block may have access to the local variables and/or formal parameters
of that block.
Inner classes include: nested top-level classes and interfaces,
member classes, local classes, and anonymous classes.
The various types of inner clases are described
in Inner Classes. The syntax for
nested top-level and member classes is covered
in Nested Top-Level and Member Classes, while the
syntax for nested top-level interfaces is covered
in Nested Top-Level Interfaces.
The syntax for local classes is described
in Local Classes.
The syntax for an anonymous class is part of an allocation
expression, as covered
in Allocation Expressions.
- Java 1.1 provides the ability to declare final
local variables, method parameters, and catch
clause parameters. final local variables, method
parameters, and catch parameters are needed to
allow local classes to access these entities within the scope of their
blocks. The syntax for final local variables is
described in Local Variables, while
final method parameters are covered
in Method formal parameters. The new syntax
for the catch clause is described
in The try Statement.
- Instance initializers are blocks of code that execute when an
instance of a class is created. Instance initializers have been added
in Java 1.1 to allow anonymous classes to perform any necessary
initialization, since anonymous classes can not define any
constructors. The syntax for instance initializers is covered
in Instance Initializers.
- As of Java 1.1, final variable declarations
do not have to include initializers. A final
variable declaration that does not include an initializer is
called a blank final. The functionality of blank finals is
described in Variable modifiers
and Final local variables.
- A class literal is a new kind of primary expression that can be
used to obtain a Class object for a particular
data type. Class literals have been added to support the new
Reflection API in Java 1.1. The syntax for class literals is
covered in Class Literals.
- An anonymous array is an array created and initialized without
using a variable initializer. The syntax for an anonymous array
is part of an allocation expression, as described
in Allocation Expressions.
