New Language Features in Java 1.1

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.