Packages

• Java classes are collected into groups, known as packages
• Used as a mechanism for grouping classes which
  • perform related functions
  • constitute a complete API specification
• To be part of a package, a Java class must begin with a package statement

  package osf.andyj;

• Class is a member of the default package (empty name) if no package name is specified
• Package name used for locating the Java bytecode file
  • interface specifications
  • method implementations
• Dependent compilation model
  • Class must be compiled before it can be imported
  • No circular dependencies among classes
• Package name consists of one or more dot-separated identifiers
  • used to construct a path to locate the bytecode for the class
  • usually done via the file system directory structure