Java Static Variables

  • Java instance variables are given separate memory for storage. If there is a need for a variable to be common to all the objects of a single java class, then the static modifier should be used in the variable declaration.
  • Any java object that belongs to that class can modify its static variables.
  • Also, an instance is not a must to modify the static variable and it can be accessed using the java class directly.
  • Static variables can be accessed by java instance methods also.
  • When the value of a constant is known at compile time it is declared ‘final’ using the ‘static’ keyword.



(3)可以直接通过  ClassName.static-Variable 对静态变量进行访问

(4)static 和final用来修饰成员变量和成员方法,可简单理解为“全局常量”。


Java Static Methods

  • Similar to static variables, java static methods are also common to classes and not tied to a java instance.
  • Good practice in java is that, static methods should be invoked with using the class name though it can be invoked using an object. ClassName.methodName(arguments) or objectName.methodName(arguments)
  • General use for java static methods is to access static fields.
  • Static methods can be accessed by java instance methods.
  • Java static methods cannot access instance variables or instance methods directly.
  • Java static methods cannot use the ‘this’ keyword.


(2)静态方法中不能用this和super关键字,不能直接访问所属类的实例变量和实例方法(就是不带static的成员变量和成员成员方法),只能访问所属类的静态成员变量和成员方法  (这点和C++中是一致的)




Java Static Classes

  • For java classes, only an inner class can be declared using the static modifier.
  • For java a static inner class it does not mean that, all their members are static. These are called nested static classes in java


posted @ 2015-01-10 22:30  CBDoctor  阅读(301)  评论(0编辑  收藏